123 results on '"Jinsheng Wen"'
Search Results
2. Signatures of a gapless quantum spin liquid in the Kitaev material Na3Co2−xZnxSbO6
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Zhongtuo Fu, Ruokai Xu, Yingqi Chen, Song Bao, Hong Du, Jiahua Min, Shuhan Zheng, Yongjun Zhang, Meifeng Liu, Xiuzhang Wang, Hong Li, Ruidan Zhong, Huiqian Luo, Jun-Ming Liu, Zhen Ma, and Jinsheng Wen
- Published
- 2023
3. Large enhancement of Curie temperature in Fe3GeTe2 by Fe intercalation in the van der Waals gap
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Yueshen Wu, Yuxiong Hu, Cong Wang, Xiang Zhou, Wei Xia, Yiwen Zhang, Jinghui Wang, Yifan Ding, Jiadian He, Peng Dong, Song Bao, Jinsheng Wen, Yanfeng Guo, Kenji Watanabe, Takashi Taniguchi, Wei Ji, Zhu-Jun Wang, and Jun Li
- Abstract
The magnetic and electrical transport properties of the two-dimensional ferromagnetic Fe3GeTe2 have proven to be a subject of intrigue, with a broad range of Curie temperatures (Tc) observed in recent studies, ranging from 160 K to 230 K, and even reaching room temperature by ionic gating. Despite these discoveries, the underlying mechanism behind the varying Tc values remains a puzzle. Here, we employed scanning transmission electron microscopy to explore the atomic structure of Fe3GeTe2 crystals exhibiting Tc values of 160, 210, and 230 K. The results of the elemental mapping reveal that Fe intercalation on the interstitial sites within the van der Waals gap is present in the high- Tc (210 and 230 K) samples. The electrical transport measurements demonstrate the presence of an exchange bias effect in these high- Tc samples, owing to the existence of ferromagnetic and antiferromagnetic interfaces, while this effect is absent in the low-Tc (160 K) samples. First-principles calculations further suggest that the Fe-intercalation layer may be responsible for the local antiferromagnetic coupling that gives rise to the exchange bias effect, and that the introduction of interlayer exchange paths greatly contributes to the enhancement of Tc. This discovery of the Fe-intercalation layer elucidates the mechanism behind the hidden antiferromagnetic ordering that underlies the enhancement of Tc in Fe3GeTe2.
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- 2023
4. Suppression of the antiferromagnetic order by Zn doping in a possible Kitaev material Na2Co2TeO6
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Zhongtuo Fu, Ruokai Xu, Song Bao, Yanyan Shangguan, Xin Liu, Zijuan Lu, Yingqi Chen, Shuhan Zheng, Yongjun Zhang, Meifeng Liu, Xiuzhang Wang, Hong Li, Huiqian Luo, Jun-Ming Liu, Zhen Ma, and Jinsheng Wen
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Physics and Astronomy (miscellaneous) ,General Materials Science - Published
- 2023
5. Enhanced low-energy magnetic excitations evidencing the Cu-induced localization in the Fe-based superconductor Fe0.98Te0.5Se0.5
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Jinghui Wang, Song Bao, Yanyan Shangguan, Zhengwei Cai, Yuan Gan, Shichao Li, Kejing Ran, Zhen Ma, B. L. Winn, A. D. Christianson, Ruidan Zhong, Jun Li, Genda Gu, and Jinsheng Wen
- Published
- 2022
6. Influence of common factors on vehicle bridge coupling vibration
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Jinsheng Wen, Zhijun Ni, Liangliang Zhang, and Tao Wu
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business.industry ,Group (mathematics) ,Computer science ,Differential equation ,Materials Science (miscellaneous) ,Structural engineering ,Function (mathematics) ,Bridge (interpersonal) ,Industrial and Manufacturing Engineering ,Vibration ,Acceleration ,Development (differential geometry) ,Decomposition method (constraint satisfaction) ,Business and International Management ,business - Abstract
As road and bridge construction industry becomes more prosperous, the vehicle’s speed and load capacity increase significantly. This paper aims at the problem of vehicle-bridge coupling vibration of highway bridges. In this paper, based on the basic theory of vehicle-bridge coupled vibration, the differential equation of vehicle-bridge coupled system is obtained. The mode decomposition method is adopted to transform the system differential equation into a matrix form. The second-order development function based on the built-in function was written by the principle of Runge-Kutta method, and the second-order time-varying differential equation group was solved. Taking the simply supported beam as an example, this paper studies the dynamic characteristics of bridge and vehicle under different speed and mass.
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- 2021
7. Axially Bound Magnetic Skyrmions: Glueing Topological Strings Across an Interface
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Kejing Ran, Yizhou Liu, Haonan Jin, Yanyan Shangguan, Yao Guang, Jinsheng Wen, Guoqiang Yu, Gerrit van der Laan, Thorsten Hesjedal, and Shilei Zhang
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Abstract
A major challenge in topological magnetism lies in the three-dimensional (3D) exploration of their magnetic textures. A recent focus has been the question of how 2D skyrmion sheets vertically stack to form distinct types of 3D topological strings. Being able to manipulate the vertical coupling should therefore provide a route to the engineering of topological states. Here, we present a new type of axially bound magnetic skyrmion string state in which the strings in two distinct materials are glued together across their interface. Using quasi-tomographic resonant elastic x-ray scattering, the 3D skyrmion profiles before and after their binding across the interface were unambiguously determined and compared. Their attractive binding is accompanied by repulsive twisting, i.e., the coupled skyrmions mutually affect each other via a compensating twisting. This state exists in chiral magnet-magnetic thin film heterostructures, providing a new arena for the engineering of 3D topological phases.
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- 2022
8. Disorder-induced broadening of the spin waves in the triangular-lattice quantum spin liquid candidate YbZnGaO4
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Zhen Ma, Zhao-Yang Dong, Jinghui Wang, Shuhan Zheng, Kejing Ran, Song Bao, Zhengwei Cai, Yanyan Shangguan, Wei Wang, M. Boehm, P. Steffens, L.-P. Regnault, Xiao Wang, Yixi Su, Shun-Li Yu, Jun-Ming Liu, Jian-Xin Li, and Jinsheng Wen
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Superconductivity (cond-mat.supr-con) ,Condensed Matter - Strongly Correlated Electrons ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed Matter - Superconductivity ,FOS: Physical sciences ,ddc:530 - Abstract
Disorder is important in the study of quantum spin liquids, but its role on the spin dynamics remains elusive. Here, we explore the disorder effect by investigating the magnetic-field dependence of the low-energy magnetic excitations in a triangular-lattice frustrated magnet YbZnGaO$_4$ with inelastic neutron scattering. With an intermediate field of 2.5 T applied along the $c$-axis, the broad continuum at zero field becomes more smeared both in energy and momentum. With a field up to 10 T, which fully polarizes the magnetic moments, we observe clear spin-wave excitations with a gap of $\sim$1.4 meV comparable to the bandwidth. However, the spectra are significantly broadened. The excitation spectra both at zero and high fields can be reproduced by performing classical Monte Carlo simulations which take into account the disorder effect arising from the random site mixing of nonmagnetic Zn$^{2+}$ and Ga$^{3+}$ ions. These results elucidate the critical role of disorder in broadening the magnetic excitation spectra and mimicking the spin-liquid features in frustrated quantum magnets., Comment: Published in PRB, 10 pages, 3 figures
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- 2021
9. Evidence for strong correlations at finite temperatures in the dimerized magnet Na2Cu2TeO6
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Yanyan Shangguan, Song Bao, Zhao-Yang Dong, Zhengwei Cai, Wei Wang, Zhentao Huang, Zhen Ma, Junbo Liao, Xiaoxue Zhao, Ryoichi Kajimoto, Kazuki Iida, David Voneshen, Shun-Li Yu, Jian-Xin Li, and Jinsheng Wen
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- 2021
10. Topological magnon insulator spin excitations in the two-dimensional ferromagnet CrBr3
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Xiaoxiang Xi, Wenda Si, Yi-Peng Gao, Jian-Xin Li, Dongjing Lin, Jinsheng Wen, Yanyan Shangguan, Jinghui Wang, Zhao-Long Gu, Shun-Li Yu, Shichao Li, D. T. Adroja, Zhao-Yang Dong, Yizhang Wu, Kejing Ran, Xiaoshan Wu, Wei Wang, Zhen Ma, Zhengwei Cai, and Song Bao
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Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Hubbard model ,Magnon ,Dirac (software) ,FOS: Physical sciences ,Fermion ,Topology ,Inelastic neutron scattering ,Condensed Matter - Strongly Correlated Electrons ,symbols.namesake ,Ferromagnetism ,symbols ,Condensed Matter::Strongly Correlated Electrons ,Hamiltonian (quantum mechanics) ,Spin-½ - Abstract
Topological magnons are bosonic analogues of topological fermions in electronic systems. They have been studied extensively by theory but rarely realized by experiment. Here, by performing inelastic neutron scattering measurements on single crystals of a two-dimensional ferromagnet CrBr$_3$, which was classified as Dirac magnon semimetal featured by the linear bands crossing at the Dirac points, we fully map out the magnetic excitation spectra, and reveal that there is an apparent gap of $\sim$3.5~meV between the acoustic and optical branches of the magnons at the K point. By collaborative efforts between experiment and theoretical calculations using a five-orbital Hubbard model obtained from first-principles calculations to derive the exchange parameters, we find that a Hamiltonian with Heisenberg exchange interactions, next-nearest-neighbor Dzyaloshinskii-Moriya (DM) interaction, and single-ion anisotropy is more appropriate to describe the system. Calculations using the model show that the lower and upper magnon bands separated by the gap exhibit Chern numbers of $\pm1$. These results indicate that CrBr$_3$ is a topological magnon insulator, where the nontrivial gap is a result of the DM interaction., Version as published in PRB Letter, main text 7 pages, supplementary materials 6 pages
- Published
- 2021
11. Antigenic cross-reactivity between Zika and dengue viruses: is it time to develop a universal vaccine?
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Jinsheng Wen and Sujan Shresta
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0301 basic medicine ,Serotype ,T-Lymphocytes ,Immunology ,Cross Reactions ,Antibodies, Viral ,Lymphocyte Activation ,Article ,Dengue fever ,Dengue ,03 medical and health sciences ,0302 clinical medicine ,Antigen ,Immunity ,medicine ,Animals ,Humans ,Immunology and Allergy ,Antigens, Viral ,Dengue vaccine ,biology ,Zika Virus Infection ,Flavivirus ,Viral Vaccines ,Zika Virus ,Dengue Virus ,medicine.disease ,Virology ,Immunity, Humoral ,Vaccination ,030104 developmental biology ,Immunization ,biology.protein ,Antibody ,030215 immunology - Abstract
Zika and the four serotypes of dengue are closely related flaviviruses that share a high degree of structural and sequence homology and co-circulate in many regions of the world. Here, we review recent studies investigating antigenic cross-reactivity between the two viruses. We discuss the pathogenic and protective roles of cross-reactive anti-viral antibody and T cell responses, respectively, in modulating the outcome of secondary dengue or Zika infection. Based on recent findings and increased incidence of severe disease in seronegative recipients of the first dengue vaccine to be licensed, we propose that the time has come to focus on developing pan-flavivirus vaccines that protect against Zika and four dengue serotypes by eliciting protective cross-reactive T cell responses while concomitantly reducing production of cross-reactive antibodies that can exacerbate disease.
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- 2019
12. Electron-phonon coupling and superconductivity in the doped topological crystalline insulator (Pb0.5Sn0.5)1−xInxTe
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Qiang Li, A. Podlesnyak, Barry Winn, Jian Sun, Yang Li, Tong Chen, A. Sapkota, Lihua Wu, Jihui Yang, Zhijun Xu, Guangyong Xu, Kejing Ran, Jinsheng Wen, John M. Tranquada, and G. D. Gu
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Superconductivity ,Materials science ,Condensed matter physics ,Phonon ,Scattering ,Doping ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Crystal ,Bond length ,Thermal conductivity ,Lattice (order) ,0103 physical sciences ,010306 general physics ,0210 nano-technology - Abstract
We present a neutron-scattering study of phonons in single crystals of (Pb0.5Sn0.5)(1-x)InxTe with x = 0 (metallic, but nonsuperconducting) and x = 0.2 (nonmetallic normal state, but superconducting). We map the phonon dispersions (more completely for x = 0) and find general consistency with theoretical calculations, except for the transverse and longitudinal optical (LO) modes at the Brillouin-zone center. At low temperature, both modes are strongly damped but sit at a finite energy (approximate to 4meV in both samples), shifting to higher energy at room temperature. These modes are soft due to a proximate structural instability driven by the sensitivity of Pb-Te and Sn-Te p-orbital hybridization to off-center displacements of the metal atoms. The impact of the soft optical modes on the low-energy acoustic modes is inferred from the low thermal conductivity, especially at low temperature. Given that the strongest electron-phonon coupling is predicted for the LO mode, which should be similar for both studied compositions, it is intriguing that only the In-doped crystal is superconducting. In addition, we observe elastic diffuse (Huang) scattering that is qualitatively explained by the difference in Pb-Te and Sn-Te bond lengths within the lattice of randomly distributed Pb and Sn sites. We also confirm the presence of anomalous diffuse low-energy atomic vibrations that we speculatively attribute to local fluctuations of individual Pb atoms between off-center sites.
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- 2020
13. Zhu et al. Reply
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Xin-Yang Zhu, Shi Wang, Zhen-Yu Jia, Li Zhu, Qi-Yuan Li, Wei-Min Zhao, Cheng-Long Xue, Yong-Jie Xu, Zhen Ma, Jinsheng Wen, Shun-Li Yu, Jian-Xin Li, and Shao-Chun Li
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General Physics and Astronomy - Published
- 2020
14. Erratum: Realization of a Metallic State in 1T - TaS2 with Persisting Long-Range Order of a Charge Density Wave [Phys. Rev. Lett. 123 , 206405 (2019)]
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Qi-Yuan Li, Li Zhu, Jinsheng Wen, Shun-Li Yu, Yong-Jie Xu, Zhen Ma, Xin-Yang Zhu, Jian-Xin Li, Shi Wang, Zhen-Yu Jia, Shao-Chun Li, Wei-Min Zhao, and Cheng-Long Xue
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Metal ,Physics ,Range (particle radiation) ,Condensed matter physics ,visual_art ,visual_art.visual_art_medium ,General Physics and Astronomy ,Order (group theory) ,State (functional analysis) ,Charge density wave ,Realization (systems) - Published
- 2020
15. Evidence for magnon-phonon coupling in the topological magnet Cu3TeO6
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Zhen Ma, Jian-Xin Li, Yanyan Shangguan, Kazuhiko Ikeuchi, Zhao-Yang Dong, Song Bao, Wei Wang, Ryoichi Kajimoto, Shun-Li Yu, Zhengwei Cai, Jinsheng Wen, Wenda Si, Xiaomeng Wang, and Jian Sun
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Physics ,Condensed Matter - Materials Science ,Strongly Correlated Electrons (cond-mat.str-el) ,Phonon ,Condensed Matter - Superconductivity ,Magnon ,Center (category theory) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Coupling (probability) ,Topology ,01 natural sciences ,Inelastic neutron scattering ,Superconductivity (cond-mat.supr-con) ,Brillouin zone ,Condensed Matter - Strongly Correlated Electrons ,Condensed Matter::Materials Science ,0103 physical sciences ,Quasiparticle ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology - Abstract
We perform thermodynamic and inelastic neutron scattering (INS) measurements to study the lattice dynamics (phonons) of a cubic collinear antiferromagnet Cu$_3$TeO$_6$ which hosts topological spin excitations (magnons). While the specific heat and thermal conductivity results show that the thermal transport is dominated by phonons, the deviation of the thermal conductivity from a pure phononic model indicates that there is a strong coupling between magnons and phonons. In the INS measurements, we find a mode in the excitation spectra at 4.5 K, which exhibits a slight downward dispersion around the Brillouin zone center. This mode disappears above the N\'{e}el temperature, and thus cannot be a phonon. Furthermore, the dispersion is distinct from that of a magnon. Instead, it can be explained by the magnon-polaron mode, which is new collective excitations resulting from the hybridization between magnons and phonons. We consider the suppression of the thermal conductivity and emergence of the magnon-polaron mode to be evidence for magnon-phonon coupling in Cu$_3$TeO$_6$., Comment: 9 pages, 4 figures, formula Cu3TeO6 updated in the title and abstract
- Published
- 2020
16. Japanese encephalitis virus–primed CD8+ T cells prevent antibody-dependent enhancement of Zika virus pathogenesis
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Yanjun Zhang, Xinyu Chen, Shengwei Jin, Dong Chen, Lan Yang, Zhiliang Duan, Weiwei Zou, Jinsheng Wen, Yongchao Zhou, Dezhou Li, Sujan Shresta, and Wenhua Zhou
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0301 basic medicine ,viruses ,030231 tropical medicine ,Immunology ,CD8-Positive T-Lymphocytes ,Cross Reactions ,Antibodies, Viral ,Article ,Virus ,Cell Line ,Zika virus ,Infectious Disease and Host Defense ,Epitopes ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Immunity ,medicine ,Animals ,Humans ,Immunology and Allergy ,Cytotoxic T cell ,Antibody-dependent enhancement ,Amino Acid Sequence ,Child ,Encephalitis, Japanese ,Encephalitis Virus, Japanese ,biology ,Zika Virus Infection ,Immune Sera ,Infant ,Zika Virus ,Japanese encephalitis ,biology.organism_classification ,medicine.disease ,Antibodies, Neutralizing ,Antibody-Dependent Enhancement ,Virology ,Mice, Inbred C57BL ,030104 developmental biology ,Animals, Newborn ,Immunoglobulin G ,Viral load - Abstract
Chen et al. show that Japanese encephalitis virus (JEV)–elicited CD8+ T cells and antibodies play protective and pathogenic roles in Zika virus–infected wild-type C57BL/6 mice, respectively, and JEV-elicited CD8+ T cells abrogate anti-JEV antibody–mediated enhancement of Zika virus infection in mice., Cross-reactive anti-flaviviral immunity can influence the outcome of infections with heterologous flaviviruses. However, it is unclear how the interplay between cross-reactive antibodies and T cells tilts the balance toward pathogenesis versus protection during secondary Zika virus (ZIKV) and Japanese encephalitis virus (JEV) infections. We show that sera and IgG from JEV-vaccinated humans and JEV-inoculated mice cross-reacted with ZIKV, exacerbated lethal ZIKV infection upon transfer to mice, and promoted viral replication and mortality upon ZIKV infection of the neonates born to immune mothers. In contrast, transfer of CD8+ T cells from JEV-exposed mice was protective, reducing the viral burden and mortality of ZIKV-infected mice and abrogating the lethal effects of antibody-mediated enhancement of ZIKV infection in mice. Conversely, cross-reactive anti-ZIKV antibodies or CD8+ T cells displayed the same pathogenic or protective effects upon JEV infection, with the exception that maternally acquired anti-ZIKV antibodies had no effect on JEV infection of the neonates. These results provide clues for developing safe anti-JEV/ZIKV vaccines., Graphical Abstract
- Published
- 2020
17. Spin dynamics of a magnetic Weyl semimetal Sr1−xMn1−ySb2
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Yanyan Shangguan, Jinsheng Wen, Jinghui Wang, Zhao-Yang Dong, Mitsutaka Nakamura, Kazuya Kamazawa, Wei Wang, Shun-Li Yu, Shichao Li, Kejing Ran, Zhengwei Cai, Jian-Xin Li, D. T. Adroja, Song Bao, and Zhen Ma
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Physics ,Condensed matter physics ,Magnon ,Exchange interaction ,Weyl semimetal ,02 engineering and technology ,Fermion ,021001 nanoscience & nanotechnology ,Coupling (probability) ,01 natural sciences ,Inelastic neutron scattering ,Magnetization ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin-½ - Abstract
Dirac matters provide a platform for exploring the interplay of their carriers with other quantum phenomena. ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{1\ensuremath{-}y}{\mathrm{Sb}}_{2}$ has been proposed to be a magnetic Weyl semimetal and provides an excellent platform to study the coupling between Weyl fermions and magnons. Here, we report comprehensive inelastic neutron scattering (INS) measurements on single crystals of ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{1\ensuremath{-}y}{\mathrm{Sb}}_{2}$, which have been well characterized by magnetization and magnetotransport measurements, both of which demonstrate that the material is a topologically nontrivial semimetal. The INS spectra clearly show a spin gap of $\ensuremath{\sim}6$ meV. The dispersion in the magnetic Mn layer extends up to about 76 meV, while that between the layers has a narrow band width of 6 meV. We find that the linear spin-wave theory using a Heisenberg spin Hamiltonian can reproduce the experimental spectra with the following parameters: a nearest-neighbor ($S{J}_{1}\ensuremath{\sim}28.0$ meV) and next-nearest-neighbor in-plane exchange interaction ($S{J}_{2}\ensuremath{\sim}9.3$ meV), interlayer exchange coupling ($S{J}_{c}\ensuremath{\sim}\ensuremath{-}0.1$ meV), and spin anisotropy constant ($SD\ensuremath{\sim}\ensuremath{-}0.07$ meV). Despite the coexistence of Weyl fermions and magnons, we find no clear evidence that the magnetic dynamics are influenced by the Weyl fermions in ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{1\ensuremath{-}y}{\mathrm{Sb}}_{2}$, possibly because that the Weyl fermions and magnons reside in the Sb and Mn layers separately, and the interlayer coupling is weak due to the quasi-two-dimensional nature of the material, as also evident from the small $S{J}_{c}$ of $\ensuremath{-}0.1$ meV.
- Published
- 2020
18. Bandgap opening in MoTe2 thin flakes induced by surface oxidation
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Jinsheng Wen, Liyuan Zhang, Shengyuan A. Yang, Mingquan He, Kedong Wang, Yuan Gan, Xu Du, Si Li, Xiaoming Ma, Yan-Ping Guo, Xuefeng Wu, Jiyuan Liang, Chang Liu, and Chang-woo Cho
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Superconductivity ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Band gap ,01 natural sciences ,Transition metal ,0103 physical sciences ,Density functional theory ,Thin film ,Metal–insulator transition ,010306 general physics ,Electronic band structure ,Quantum tunnelling - Abstract
Recently, the layered transition metal dichalcogenide 1T′-MoTe2 has generated considerable interest due to their superconducting and non-trivial topological properties. Here, we present a systematic study on 1T′-MoTe2 single-crystal and exfoliated thin-flakes by means of electrical transport, scanning tunnelling microscope (STM) measurements and band structure calculations. For a bulk sample, it exhibits large magneto-resistance (MR) and Shubnikov–de Hass oscillations in ρxx and a series of Hall plateaus in ρxy at low temperatures. Meanwhile, the MoTe2 thin films were intensively investigated with thickness dependence. For samples, without encapsulation, an apparent transition from the intrinsic metallic to insulating state is observed by reducing thickness. In such thin films, we also observed a suppression of the MR and weak anti-localization (WAL) effects. We attributed these effects to disorders originated from the extrinsic surface chemical reaction, which is consistent with the density functional theory (DFT) calculations and in-situ STM results. In contrast to samples without encapsulated protection, we discovered an interesting superconducting transition for those samples with hexagonal Boron Nitride (h-BN) film protection. Our results indicate that the metallic or superconducting behavior is its intrinsic state, and the insulating behavior is likely caused by surface oxidation in few layer 1T’-MoTe2 flakes.
- Published
- 2020
19. Anisotropic scattering continuum induced by crystal symmetry reduction in atomically thin α–RuCl3
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Xiaoxiang Xi, Jinsheng Wen, Libo Gao, Jian-Xin Li, Shun-Li Yu, Hang Zheng, Jie Xu, Kejing Ran, and Dongjing Lin
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Physics ,Phase transition ,Condensed matter physics ,Phonon ,Scattering ,02 engineering and technology ,Fermion ,021001 nanoscience & nanotechnology ,01 natural sciences ,symbols.namesake ,0103 physical sciences ,symbols ,Topological order ,van der Waals force ,Quantum spin liquid ,010306 general physics ,0210 nano-technology ,Ground state - Abstract
Kitaev quantum spin liquids described by the Kitaev model represent an exotic state of matter with long-range entangled spins and topological order, which hold promise for quantum computation. $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$, a material with van der Waals layered structure, is shown to be proximate to such a state recently. Here we report Raman spectroscopy of atomically thin $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$. New phonon modes emerge at low temperature, signifying a phase transition to a crystal structure with lowered symmetry. The Fano line shape of two low-energy phonon modes and the magnetic scattering continuum in bulk $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$, which evidence fractionalized Majorana fermions of the proximate quantum spin liquid, persist to the trilayer. Polarization-dependent measurements reveal increased anisotropy of the Kitaev exchange constants when approaching the two-dimensional limit. Our results demonstrate an intimate relation between the crystal structure and the symmetry of the proximate quantum spin liquid ground state.
- Published
- 2020
20. Disorder-induced spin-liquid-like behavior in kagome-lattice compounds
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Kejing Ran, Yanyan Shangguan, Jian-Xin Li, Shun-Li Yu, Zhen Ma, Jinghui Wang, Zhengwei Cai, Zhao-Yang Dong, Yinghao Zhu, Jinsheng Wen, Haifeng Li, Song Bao, Richard A. Mole, Si Wu, Dehong Yu, Wei Wang, and Guochu Deng
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Physics ,Spins ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed Matter - Superconductivity ,FOS: Physical sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Inelastic neutron scattering ,Superconductivity (cond-mat.supr-con) ,Condensed Matter - Strongly Correlated Electrons ,Crystallography ,Linear term ,Lattice (order) ,0103 physical sciences ,Antiferromagnetism ,Random mixing ,Isostructural ,Quantum spin liquid ,010306 general physics ,0210 nano-technology - Abstract
Quantum spin liquids (QSLs) are an exotic state of matter that is subject to extensive research. However, the relationship between the ubiquitous disorder and the QSL behaviors is still unclear. Here, by performing comparative experimental studies on two kagom\'{e}-lattice QSL candidates, Tm$_3$Sb$_3$Zn$_2$O$_{14}$ and Tm$_3$Sb$_3$Mg$_2$O$_{14}$, which are isostructural to each other but with strong and weak structural disorder, respectively, we show unambiguously that the disorder can induce spin-liquid-like features. In particular, both compounds show dominant antiferromagnetic interactions with a Curie-Weiss temperature of -17.4 and -28.7 K for Tm$_3$Sb$_3$Zn$_2$O$_{14}$ and Tm$_3$Sb$_3$Mg$_2$O$_{14}$, respectively, but remain disordered down to about 0.05 K. Specific heat results suggest the presence of gapless magnetic excitations characterized by a residual linear term. Magnetic excitation spectra obtained by inelastic neutron scattering (INS) at low temperatures display broad continua. All these observations are consistent with those of a QSL. However, we find in Tm$_3$Sb$_3$Zn$_2$O$_{14}$ which has strong disorder resulting from the random mixing of the magnetic Tm$^{3+}$ and nonmagnetic Zn$^{2+}$, that the low-energy magnetic excitations observed in the specific heat and INS measurements are substantially enhanced, compared to those of Tm$_3$Sb$_3$Mg$_2$O$_{14}$ which has much less disorder. We believe that the effective spins of the Tm$^{3+}$ ions in the Zn$^{2+}$/Mg$^{2+}$ sites give rise to the low-energy magnetic excitations, and the amount of the random occupancy determines the excitation strength. These results provide direct evidence of the mimicry of a QSL caused by disorder., Comment: Version as published in PRB, 5 figures, 11 pages
- Published
- 2020
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21. Realization of a Metallic State in 1T−TaS2 with Persisting Long-Range Order of a Charge Density Wave
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Jian-Xin Li, Shao-Chun Li, Qi-Yuan Li, Shi Wang, Li Zhu, Jinsheng Wen, Xin-Yang Zhu, Shun-Li Yu, Zhen-Yu Jia, Cheng-Long Xue, Zhen Ma, Yong-Jie Xu, and Wei-Min Zhao
- Subjects
Condensed Matter::Quantum Gases ,Range (particle radiation) ,Materials science ,Condensed matter physics ,Mott insulator ,Electric potential energy ,Doping ,General Physics and Astronomy ,Alkali metal ,01 natural sciences ,law.invention ,law ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,Scanning tunneling microscope ,010306 general physics ,Charge density wave ,Excitation - Abstract
Metallization of 1T-TaS_{2} is generally initiated at the domain boundary of a charge density wave (CDW), at the expense of its long-range order. However, we demonstrate in this study that the metallization of 1T-TaS_{2} can be also realized without breaking the long-range CDW order upon surface alkali doping. By using scanning tunneling microscopy, we find the long-range CDW order is always persisting, and the metallization is instead associated with additional in-gap excitations. Interestingly, the in-gap excitation is near the top of the lower Hubbard band, in contrast to a conventional electron-doped Mott insulator where it is beneath the upper Hubbard band. In combination with the numerical calculations, we suggest that the appearance of the in-gap excitations near the lower Hubbard band is mainly due to the effectively reduced on-site Coulomb energy by the adsorbed alkali ions.
- Published
- 2019
22. Evidence for a Dirac nodal-line semimetal in SrAs3
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Song Bao, Jinsheng Wen, Zhen Ma, Zhaopeng Guo, Shichao Li, Xingchen Pan, Fengqi Song, Jinghui Wang, Jian Sun, Dongzhi Fu, Kejing Ran, Rui Wang, Rui Yu, and Zhengwei Cai
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Physics ,Chiral anomaly ,Condensed Matter - Materials Science ,Multidisciplinary ,Magnetoresistance ,Condensed matter physics ,Condensed Matter - Superconductivity ,Dirac (software) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Quantum oscillations ,02 engineering and technology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Semimetal ,Superconductivity (cond-mat.supr-con) ,Loop (topology) ,Geometric phase ,0103 physical sciences ,State of matter ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology - Abstract
Dirac nodal-line semimetals with the linear bands crossing along a line or loop, represent a new topological state of matter. Here, by carrying out magnetotransport measurements and performing first-principle calculations, we demonstrate that such a state has been realized in high-quality single crystals of SrAs3. We obtain the nontrivial pi Berry phase by analysing the Shubnikov-de Haas quantum oscillations. We also observe a robust negative longitudinal magnetoresistance induced by the chiral anomaly. Accompanying first-principles calculations identify that a single hole pocket enclosing the loop nodes is responsible for these observations., Comment: Version as published in Science Bulletin
- Published
- 2018
23. Observation of topological superconductivity on the surface of an iron-based superconductor
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Peng Zhang, Jinsheng Wen, Koichiro Yaji, Shik Shin, Genda Gu, Takahiro Hashimoto, Kozo Okazaki, Yuichi Ota, Hong Ding, Takeshi Kondo, and Zhijun Wang
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Surface (mathematics) ,FOS: Physical sciences ,02 engineering and technology ,Topology ,01 natural sciences ,Topological quantum computer ,Superconductivity (cond-mat.supr-con) ,Condensed Matter - Strongly Correlated Electrons ,symbols.namesake ,Condensed Matter::Superconductivity ,0103 physical sciences ,010306 general physics ,Surface states ,Physics ,Superconductivity ,Condensed Matter - Materials Science ,Multidisciplinary ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed Matter - Superconductivity ,Fermi level ,Materials Science (cond-mat.mtrl-sci) ,Heterojunction ,021001 nanoscience & nanotechnology ,Iron-based superconductor ,MAJORANA ,symbols ,0210 nano-technology - Abstract
Topological superconductors, whose edge hosts Majorana bound states or Majorana fermions that obey non-Abelian statistics, can be used for low-decoherence quantum computations. Most of the proposed topological superconductors are realized with spin-helical states through proximity effect to BCS superconductors. However, such approaches are difficult for further studies and applications because of the low transition temperatures and complicated hetero-structures. Here by using high-resolution spin-resolved and angle-resolved photoelectron spectroscopy, we discover that the iron-based superconductor FeTe1-xSex (x = 0.45, Tc = 14.5 K) hosts Dirac-cone type spin-helical surface states at Fermi level, which open an s-wave SC gap below Tc. Our study proves that the surface states of FeTe0.55Se0.45 are 2D topologically superconducting, and thus provides a simple and possibly high-Tc platform for realizing Majorana fermions., 10 pages, 5 figures. 1706.05163, 1803.00845 and 1803.00846 are a series of studies on topological superconductivity and topological states in iron-based superconductors
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- 2018
24. Activation and Regulation of Blood Vδ2 T Cells Are Amplified by TREM-1+ during Active Pulmonary Tuberculosis
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Yongjian Wu, Xi Huang, Mei Zhang, Ngiambudulu M. Francisco, Siqi Ming, Jinsheng Wen, Ting Liu, Xi Liu, Yin-Min Fang, Chunxin Liao, Li Ding, Zi Li, Sitang Gong, Muazzam Jacobs, Minhao Wu, Zhiming Ma, and Miao Li
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0301 basic medicine ,medicine.diagnostic_test ,biology ,Chemistry ,Immunology ,biology.organism_classification ,Phenotype ,Molecular biology ,Flow cytometry ,Mycobacterium tuberculosis ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Immune system ,Pulmonary tuberculosis ,medicine ,Immunology and Allergy ,Receptor ,Intracellular ,Function (biology) ,030215 immunology - Abstract
Triggering receptor expressed on myeloid cells 1 (TREM-1) is a receptor mainly expressed on myeloid cells, and it plays an important role in modulating immune response against infectious agents. The function of TREM-1 on nonmyeloid cells such as Vδ2 T cells has not been characterized, and their role in pulmonary tuberculosis (TB) remains unclear. To assess the expression of TREM-1 on blood Vδ2 T cells from pulmonary TB patients and investigate its mechanism of induction, we exploited flow cytometry analysis to study the expression of TREM-1 on Vδ2 T cells from active pulmonary TB patients and control subjects. In this study we demonstrate that TREM-1 (TREM-1+) is highly expressed on Vδ2 T cells of patients with active pulmonary TB. Unlike TREM-1−–expressing Vδ2 T cells, TREM-1+–producing Vδ2 T cells display APC-like phenotypes. Surprisingly, TREM-1+ signaling promotes the Ag-presenting capability of Vδ2 T cells to induce the CD4+ T cell response. TREM-1+Vδ2 T cells induced the proliferation and differentiation of naive CD4+ T cells, as well as the elimination of intracellular mycobacteria. We identified TREM-1+ (but not TREM-1−) as an Ag-presentation amplifier on human blood Vδ2 T cells, and data shed new light on the regulation of Vδ2 T cells in the phase of innate and adaptive immune responses against Mycobacterium tuberculosis infection. Targeting TREM-1+Vδ2 T cells may be a promising approach for TB therapy.
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- 2018
25. Observation of a Ubiquitous (π, π)-Type Nematic Superconducting Order in the Whole Superconducting Dome of Ultra-Thin BaFe2–x Ni x As2 Single Crystals
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Yulong Huang, Yang-Yang Lv, Wei Chen, A. N. Vasiliev, Yu Dong, Jian-Xin Li, Labao Zhang, Jie Yuan, Huabing Wang, Liang Li, M. Abdel-Hafiez, Jun Li, Shiliang Li, Jinsheng Wen, Yueshen Wu, Song Bao, Junfeng Wang, Wanghao Tian, and Peiheng Wu, Haipeng Zhu, Kui Jin, Shun-Li Yu, Jinghui Wang, and Zuyu Xu
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Superconductivity ,Dome (geology) ,Materials science ,Condensed matter physics ,Liquid crystal ,General Physics and Astronomy ,Order (group theory) ,Type (model theory) - Published
- 2021
26. Ground states of Au2Pb and pressure-enhanced superconductivity
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Zili Feng, Tong Chen, Jinsheng Wen, Jinghui Wang, Qun Chen, Juefei Wu, Dingyu Xing, Zhaopeng Guo, Youguo Shi, Chi Ding, and Jian Sun
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Diffraction ,Superconductivity ,Physics ,Condensed matter physics ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,01 natural sciences ,Conventional superconductor ,Ab initio quantum chemistry methods ,Phase (matter) ,High pressure ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,Ambient pressure - Abstract
$\mathrm{A}{\mathrm{u}}_{2}\mathrm{Pb}$ is a candidate of natural topological superconductors that has attracted much attention in the last few years. Combining ab initio calculations with machine-learning accelerated crystal structure searches, we have found two ground states of $\mathrm{A}{\mathrm{u}}_{2}\mathrm{Pb}$: $Pca{2}_{1}$ phase at ambient pressure and $I\overline{4}2d$ phase at high pressure. The $Pca{2}_{1}$ phase is energetically more favorable than the known Pbcn structure and can be a candidate for x-ray diffraction refinement; our calculations suggest that high-pressure $I\overline{4}2d$ is a conventional superconductor. By the high-pressure electric resistance measurements, we observed evidence of a ${T}_{c}$ enhancement. ${T}_{c}$ reaches a maximum value of around 4 K at 5 GPa, then decreases with further compression. The superconductivity can remain unchanged after pressure releasing, in line with our theoretical predictions. These results show that $\mathrm{A}{\mathrm{u}}_{2}\mathrm{Pb}$ exhibits abundant behaviors under varied pressure and temperature, which can help to understand how to adjust its electronic properties by pressure.
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- 2019
27. Quasiparticle Evidence for the Nematic State above Tc in SrxBi2Se3
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Jinsheng Wen, Jinghui Wang, Kazushige Machida, Shunichiro Kittaka, Zhixiang Shi, Yue Sun, Toshiro Sakakibara, Tsuyoshi Tamegai, and Xiangzhuo Xing
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Superconductivity ,Physics ,Zeeman effect ,Condensed matter physics ,General Physics and Astronomy ,Crystal structure ,Condensed Matter::Soft Condensed Matter ,symbols.namesake ,Liquid crystal ,Condensed Matter::Superconductivity ,Density of states ,Quasiparticle ,symbols ,Cuprate ,Anisotropy - Abstract
In the electronic nematic state, an electronic system has a lower symmetry than the crystal structure of the same system. Electronic nematic states have been observed in various unconventional superconductors such as cuprate, iron-based, heavy-fermion, and topological superconductors. The relation between nematicity and superconductivity is a major unsolved problem in condensed matter physics. By angle-resolved specific heat measurements, we report bulk quasiparticle evidence of nematicity in the topological superconductor Sr_{x}Bi_{2}Se_{3}. The specific heat exhibited a clear twofold symmetry despite the threefold symmetric lattice. Most importantly, the twofold symmetry appeared in the normal state above the superconducting transition temperature. This is explained by the angle-dependent Zeeman effect due to the anisotropic density of states in the nematic phase. Such results highlight the interrelation between nematicity and unconventional superconductivity.
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- 2019
28. Quasiparticle Evidence for the Nematic State above T_{c} in Sr_{x}Bi_{2}Se_{3}
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Yue, Sun, Shunichiro, Kittaka, Toshiro, Sakakibara, Kazushige, Machida, Jinghui, Wang, Jinsheng, Wen, Xiangzhuo, Xing, Zhixiang, Shi, and Tsuyoshi, Tamegai
- Abstract
In the electronic nematic state, an electronic system has a lower symmetry than the crystal structure of the same system. Electronic nematic states have been observed in various unconventional superconductors such as cuprate, iron-based, heavy-fermion, and topological superconductors. The relation between nematicity and superconductivity is a major unsolved problem in condensed matter physics. By angle-resolved specific heat measurements, we report bulk quasiparticle evidence of nematicity in the topological superconductor Sr_{x}Bi_{2}Se_{3}. The specific heat exhibited a clear twofold symmetry despite the threefold symmetric lattice. Most importantly, the twofold symmetry appeared in the normal state above the superconducting transition temperature. This is explained by the angle-dependent Zeeman effect due to the anisotropic density of states in the nematic phase. Such results highlight the interrelation between nematicity and unconventional superconductivity.
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- 2019
29. Superconductivity in Potassium-intercalated Td-WTe2
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Qi-Yuan Li, Shichao Li, Yang-Yang Lv, Jinsheng Wen, Yu-Lei Chen, Xin-Yang Zhu, Li Zhu, Shao-Chun Li, and Zhen-Yu Jia
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Magnetoresistance ,Intercalation (chemistry) ,Scanning tunneling spectroscopy ,Weyl semimetal ,FOS: Physical sciences ,Bioengineering ,02 engineering and technology ,01 natural sciences ,law.invention ,Superconductivity (cond-mat.supr-con) ,Condensed Matter::Materials Science ,symbols.namesake ,law ,Condensed Matter::Superconductivity ,0103 physical sciences ,General Materials Science ,010306 general physics ,Anisotropy ,Superconductivity ,Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Mechanical Engineering ,Condensed Matter - Superconductivity ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,symbols ,Scanning tunneling microscope ,van der Waals force ,0210 nano-technology - Abstract
To realize topological superconductor is one of the most attracting topics because of its great potential in quantum computation. In this study, we successfully intercalate potassium (K) into the van der Waals gap of type II Weyl semimetal WTe2, and discover the superconducting state in KxWTe2 through both electrical transport and scanning tunneling spectroscopy measurements. The superconductivity exhibits an evident anisotropic behavior. Moreover, we also uncover the coexistence of superconductivity and the positive magneto-resistance state. Structural analysis substantiates the negligible lattice expansion induced by the intercalation, therefore suggesting K-intercalated WTe2 still hosts the topological nontrivial state. These results indicate that the K-intercalated WTe2 may be a promising candidate to explore the topological superconductor., Comment: 17 pages, 4 figures
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- 2019
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30. Ionic-liquid-gating induced protonation and superconductivity in FeSe, FeSe0.93S0.07, ZrNCl, 1T-TaS2, and Bi2Se3
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Cong Wang, Zhen Ma, Jianping Sun, Hechang Lei, Yuan Li, J. L. Zhang, Ming-Wei Ma, Ze Hu, Weiqiang Yu, Shuang Jia, Wen-Long Ma, Jiaqiang Yan, Wei Ji, Yi Cui, Pu Yu, Jinguang Cheng, and Jinsheng Wen
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Superconductivity ,Materials science ,Condensed Matter - Superconductivity ,General Physics and Astronomy ,FOS: Physical sciences ,Protonation ,02 engineering and technology ,Electric transport ,Gating ,021001 nanoscience & nanotechnology ,01 natural sciences ,Superconductivity (cond-mat.supr-con) ,chemistry.chemical_compound ,Magnetization ,Crystallography ,chemistry ,Relaxation rate ,Interstitial defect ,0103 physical sciences ,Ionic liquid ,010306 general physics ,0210 nano-technology - Abstract
We report protonation in several compounds by an ionic-liquid-gating method, with optimized gating conditions. This leads to single superconducting phases for several compounds. Non-volatility of protons allow post-gating magnetization and transport measurements. The superconducting transition temperature $T_C$ is enhanced to 43.5~K for FeSe$_{0.93}$S$_{0.07}$, and 41~K for FeSe after protonation. Superconductivity with $T_c$$\approx$15~K for ZrNCl, $\approx$7.2~K for 1$T$-TaS$_2$, and $\approx$3.8~K for Bi$_2$Se$_3$ are induced after protonation. Electric transport in protonated FeSe$_{0.93}$S$_{0.07}$ confirms high-temperature superconductivity. Our $^{1}$H NMR measurements on protonated FeSe$_{1-x}$S$_{x}$ reveal enhanced spin-lattice relaxation rate $1/^{1}T_1$ with increasing $x$, which is consistent with LDA calculations that H$^{+}$ are located in the interstitial sites close to the anions., Comment: 4 pages, 7 figures
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- 2019
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31. Evidence for singular-phonon-induced nematic superconductivity in a topological superconductor candidate Sr$_{0.1}$Bi$_2$Se$_3$
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Jinsheng Wen, Shichao Li, Seiko Ohira-Kawamura, Zhen Ma, Petr Čermák, Kejing Ran, Youtian Zhang, Astrid Schneidewind, Xiangang Wan, Zhengwei Cai, Jinghui Wang, Sergey Y. Savrasov, Song Bao, and Kenji Nakajima
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0301 basic medicine ,Electronic properties and materials ,cond-mat.supr-con ,Phonon ,Science ,General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Electron ,Topology ,Article ,General Biochemistry, Genetics and Molecular Biology ,Inelastic neutron scattering ,Superconducting properties and materials ,Superconductivity (cond-mat.supr-con) ,03 medical and health sciences ,Condensed Matter::Materials Science ,Liquid crystal ,Condensed Matter::Superconductivity ,lcsh:Science ,Physics ,Superconductivity ,Multidisciplinary ,Condensed Matter - Superconductivity ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,030104 developmental biology ,Pairing ,Topological insulator ,lcsh:Q ,Condensed Matter::Strongly Correlated Electrons ,ddc:500 ,0210 nano-technology ,Single crystal - Abstract
Superconductivity mediated by phonons is typically conventional, exhibiting a momentum-independent s-wave pairing function, due to the isotropic interactions between electrons and phonons along different crystalline directions. Here, by performing inelastic neutron scattering measurements on a superconducting single crystal of Sr0.1Bi2Se3, a prime candidate for realizing topological superconductivity by doping the topological insulator Bi2Se3, we find that there exist highly anisotropic phonons, with the linewidths of the acoustic phonons increasing substantially at long wavelengths, but only for those along the [001] direction. This observation indicates a large and singular electron-phonon coupling at small momenta, which we propose to give rise to the exotic p-wave nematic superconducting pairing in the MxBi2Se3 (M = Cu, Sr, Nb) superconductor family. Therefore, we show these superconductors to be example systems where electron-phonon interaction can induce more exotic superconducting pairing than the s-wave, consistent with the topological superconductivity., Superconductivity mediated by phonons is usually conventional due to isotropic electron-phonon coupling. Here, Wang et al. report highly anisotropic phonons only along [001] direction in Sr0.1Bi2Se3, indicating a singular electron-phonon coupling which favors a p-wave nematic superconductivity scenario.
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- 2019
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32. Experimental identification of quantum spin liquids
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Shiyan Li, Shun-Li Yu, Jinsheng Wen, Weiqiang Yu, and Jian-Xin Li
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Physics ,Phase transition ,Condensed Matter - Materials Science ,Strongly Correlated Electrons (cond-mat.str-el) ,Spontaneous symmetry breaking ,Condensed Matter - Superconductivity ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Quantum entanglement ,Condensed Matter Physics ,lcsh:Atomic physics. Constitution and properties of matter ,Electronic, Optical and Magnetic Materials ,lcsh:QC170-197 ,Superconductivity (cond-mat.supr-con) ,Condensed Matter - Strongly Correlated Electrons ,Quantum mechanics ,lcsh:TA401-492 ,lcsh:Materials of engineering and construction. Mechanics of materials ,Quantum spin liquid ,Quantum information science ,Absolute zero ,Quantum ,Quantum fluctuation - Abstract
In condensed matter physics, there is a novel phase termed "quantum spin liquid", in which strong quantum fluctuations prevent the long-range magnetic order from being established, and so the electron spins do not form an ordered pattern but remain "liquid" like even at absolute zero temperature. Such a phase is not involved with any spontaneous symmetry breaking and local order parameter, and to understand it is beyond the conventional phase transition theory. Due to the rich physics and exotic properties of quantum spin liquids, such as the long-range entanglement and fractional quantum excitations, which are believed to hold great potentials in quantum communication and computation, they have been intensively studied since the concept was proposed in 1973 by P. W. Anderson. Currently, experimental identifications of a quantum spin liquid still remain as a great challenge. Here, we highlight some interesting experimental progress that has been made recently. We also discuss some outstanding issues and raise questions that we consider to be important for future research., Comment: A short review paper published in npj Quantum Materials. Due to the limitation on the number of references, we are very unfortunate to miss many excellent ones
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- 2019
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33. Pressure-induced structural and electronic transitions in bismuth iodide
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Xiaomeng Wang, Qun Chen, Jian Sun, Chi Ding, Juefei Wu, Jinghui Wang, Tong Chen, Pengchao Lu, Hao Gao, and Jinsheng Wen
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Superconductivity ,Phase transition ,Materials science ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Coupling (probability) ,01 natural sciences ,Crystal ,Tetragonal crystal system ,symbols.namesake ,Crystallography ,Ab initio quantum chemistry methods ,Condensed Matter::Superconductivity ,Phase (matter) ,0103 physical sciences ,symbols ,010306 general physics ,0210 nano-technology ,Raman spectroscopy - Abstract
Using a machine-learning accelerated crystal structural search, and ab initio calculations together with high-pressure Raman measurements, we study the crystal and electronic structures of bismuth iodide (BiI) systematically up to 50 GPa. We find that the ambient $C2/m$ phase ($\ensuremath{\beta}\ensuremath{-}\mathrm{B}{\mathrm{i}}_{4}{\mathrm{I}}_{4}$) transforms across a tetragonal $P{4}_{2}/mmc$ phase at 8.5 GPa and finally to a hexagonal $P{6}_{3}/mmc$ phase at 28.2 GPa. Our high-pressure Raman experiments identify a phase transition at around 8.6 GPa, and the experimental Raman modes evolution agrees with our calculations reasonably. Band-structures calculations suggest the BiI system undergoes a pressure-induced topological phase transition from a topological metal ($P{4}_{2}/mmc$ phase) to a trivial metal (the $P{6}_{3}/mmc$ phase). Our electron-phonon coupling calculations show both the $P{4}_{2}/mmc$ and $P{6}_{3}/mmc$ phases are superconductors and the estimated superconducting critical temperature agrees with previous measurements. Our study shows the previously reported pressure-induced superconductivity in BiI should originate from structure phase transitions.
- Published
- 2018
34. The diagnostic potential of MPT63-derived HLA-A*0201-restricted CD8+T-cell epitopes for active pulmonary tuberculosis
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Zhigang Xu, Huifang Liu, Jinsheng Wen, Qingjun Jia, Xinyu Chen, Juanjuan Xu, Bokun Chen, Zhiliang Duan, and Dezhou Li
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Tuberculosis ,biology ,Immunology ,biology.organism_classification ,medicine.disease ,Microbiology ,Peripheral blood mononuclear cell ,Virology ,Epitope ,Mycobacterium tuberculosis ,Mycobacterium tuberculosis complex ,medicine ,Cytotoxic T cell ,Tuberculosis vaccines ,CD8 - Abstract
MPT63 protein is found only in Mycobacterium tuberculosis complex, including M. tuberculosis and M. bovis. Detection of MPT63-specific IFN-γ-secreting T cells could be useful for the diagnosis of tuberculosis (TB) diseases. In the present study, the HLA-A*0201 restriction of ten predicted MPT63-derived CD8(+) T-cell epitopes was assessed on the basis of T2 cell line and HLA-A*0201 transgenic mice. The diagnostic potential of immunogenic peptides in active pulmonary TB patients was evaluated using an IFN-γ enzyme-linked immunospot assay. It was found that five peptides bound to HLA-A*0201 with high affinity, whereas the remaining peptides exhibited low affinity for HLA-A*0201. Five immunogenic peptides (MPT6318-26 , MPT6329-37 , MPT6320-28 , MPT635-14 and MPT6310-19 ) elicited large numbers of cytotoxic IFN-γ-secreting T cells in HLA-A*0201 transgenic mice. Each of the five immunogenic peptides was recognized by peripheral blood mononuclear cells from 45% to 73% of 40 HLA-A*0201 positive TB patients. The total diagnostic sensitivity of the five immunogenic peptides was higher than that of a T-SPOT.TB assay (based on ESAT-6 and CFP-10) (93% versus 90%). It is noticeable that the diagnostic sensitivity of the combination of five immunogenic peptides and T-SPOT.TB assay reached 100%. These MPT63-derived HLA-A*0201-restricted CD8(+) T-cell epitopes would likely contribute to the immunological diagnosis of M. tuberculosis infection and may provide the components for designing an effective TB vaccine.
- Published
- 2015
35. Dengue virus envelope protein domain III-elicited antibodies mediate cross-protection against Zika virus in a mouse model
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Yongchao Zhou, Weiwei Zou, Yanjun Zhang, Dong Chen, Lan Yang, Jinsheng Wen, and Zhiliang Duan
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Male ,Cancer Research ,Cross Protection ,viruses ,T cell ,Protein domain ,Dengue virus ,Biology ,Antibodies, Viral ,medicine.disease_cause ,Zika virus ,Mice ,Protein Domains ,Viral Envelope Proteins ,Antigen ,Neutralization Tests ,Virology ,Chlorocebus aethiops ,medicine ,Animals ,Vero Cells ,Gene ,Zika Virus Infection ,Immunization, Passive ,virus diseases ,Zika Virus ,Dengue Virus ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Antibodies, Neutralizing ,In vitro ,Mice, Inbred C57BL ,Disease Models, Animal ,Infectious Diseases ,medicine.anatomical_structure ,Animals, Newborn ,biology.protein ,Female ,Immunization ,Antibody ,Immunity, Maternally-Acquired - Abstract
Dengue virus (DENV) and Zika virus (ZIKV) are antigenically related mosquito-transmitted viruses which represent a big public health problem. Although the antigenic cross-reactivity between two viruses were intensively investigated at the antibody and T cell levels, how DENV envelope protein domain III (EDIII)-elicited antibodies (Abs) impact the outcome of ZIKV infection is uncertain. Here, our results show that the sera isolated from DENV-EDIII-immunized wild-type mice recognized ZIKV-EDIII and cross-neutralized ZIKV in vitro. Passive transfer of DENV-EDIII-immune sera protected 1-day-old mice against lethal ZIKV challenge. Finally, maternally acquired anti-DENV-EDIII Abs significantly increased the survival of 1-day-old mice born to DENV-EDIII-immunized mothers post ZIKV challenge. These results reveal that DENV-EDIII-induced Abs provide cross-protection against ZIKV and may not mediate the Ab-dependent enhancement of ZIKV infection at the concentration used here. The present study would contribute to the development and application of DENV-EDIII-based vaccines.
- Published
- 2020
36. ESIPT-based ratiometric fluorescent probe for highly selective and sensitive sensing and bioimaging of group IIIA ions in living cancer cells and zebrafish
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Feng Ding, Chuchu Xu, Jinsheng Wen, Jianliang Shen, Wei Xiong, Yuna Qian, LileiZhang, Xiaojun He, and Jinyi Fan
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Process Chemistry and Technology ,General Chemical Engineering ,Metal ions in aqueous solution ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Ion ,chemistry ,Group (periodic table) ,Intramolecular force ,Molecule ,Gallium ,0210 nano-technology ,Indium - Abstract
Gallium, aluminum, and indium belong to Group IIIA of the periodic table with similar chemical properties, which were a double-edged sword for living organisms. Therefore, it's particularly important to detect the content of Group IIIA in organisms. Obviously, the fluorescent probe method has become a mainstream method for detecting metal ions with advantages of convenience and high efficiency. Unfortunately, fluorescent probes that can simultaneously detect these three metal ions are rarely reported. 3-hydroxyflavone (3-HF) is a highly focused molecule with chemical and photochemical properties and have great potential for bioimaging applications as sensors with excited-state intramolecular proton transfer (ESIPT). Here, 3-HF as ratiometric fluorescence probes have been developed for responding to Group IIIA ions including Ga(III), Al(III) and In(III) ions with ESIPT-based mechanism. 3-HF displayed highly specific sensing for Group IIIA ions over other cations with a green fluorescence transformation into blue fluorescence by the formation of 2:1 complexes. However, rapid response toward Group IIIA ions was developed using ratiometric fluorescence with wide pH range and good reversibility, and the response mechanism of 3-HF toward Group IIIA ions was annotated by density functional theory (DFT). Furthermore, the biological applicability of 3-HF has shown that 3-HF were able to detect and image Group IIIA ions in cells. Additionally, using a zebrafish model, we exhibited the capability of this 3-HF probe for detecting and imaging Group IIIA ions in zebrafish. This work achieves the detection and imaging of Group IIIA simultaneously by 3-HF probe in living cells and zebrafish and provides another example for “ESIPT OFF”.
- Published
- 2020
37. Superconductivity in Potassium-Intercalated T
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Li, Zhu, Qi-Yuan, Li, Yang-Yang, Lv, Shichao, Li, Xin-Yang, Zhu, Zhen-Yu, Jia, Y B, Chen, Jinsheng, Wen, and Shao-Chun, Li
- Abstract
To realize a topological superconductor is one of the most attracting topics because of its great potential in quantum computation. In this study, we successfully intercalate potassium (K) into the van der Waals gap of type II Weyl semimetal WTe
- Published
- 2018
38. Unusual phonon density of states and response to the superconducting transition in the In-doped topological crystalline insulator Pb0.5Sn0.5Te
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Tong Chen, Barry Winn, Guangyong Xu, Zhengwei Cai, Song Bao, Ruidan Zhong, Kejing Ran, Zhen Ma, John M. Tranquada, Yuan Gan, Jian Sun, Shichao Li, Genda Gu, Jinsheng Wen, Jinghui Wang, and Andrew D. Christianson
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Superconductivity ,Physics ,Phonon ,Doping ,02 engineering and technology ,BCS theory ,021001 nanoscience & nanotechnology ,Topology ,01 natural sciences ,Omega ,Inelastic neutron scattering ,Electrical resistivity and conductivity ,Condensed Matter::Superconductivity ,0103 physical sciences ,Density functional theory ,010306 general physics ,0210 nano-technology - Abstract
We present inelastic neutron scattering results of phonons in ${({\mathrm{Pb}}_{0.5}{\mathrm{Sn}}_{0.5})}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{Te}$ powders, with $x=0$ and 0.3. The $x=0$ sample is a topological crystalline insulator, and the $x=0.3$ sample is a superconductor with a bulk superconducting transition temperature ${T}_{c}$ of 4.7 K. In both samples, we observe unexpected van Hove singularities in the phonon density of states at energies of 1--2.5 meV, suggestive of local modes. On cooling the superconducting sample through ${T}_{c}$, there is an enhancement of these features for energies below twice the superconducting-gap energy. We further note that the superconductivity in ${({\mathrm{Pb}}_{0.5}{\mathrm{Sn}}_{0.5})}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{Te}$ occurs in samples with normal-state resistivities of order 10 $\mathrm{m}\mathrm{\ensuremath{\Omega}}\phantom{\rule{0.16em}{0ex}}\mathrm{cm}$, indicative of bad-metal behavior. Calculations based on density functional theory suggest that the superconductivity is easily explainable in terms of electron-phonon coupling; however, they completely miss the low-frequency modes and do not explain the large resistivity. While the bulk superconducting state of ${({\mathrm{Pb}}_{0.5}{\mathrm{Sn}}_{0.5})}_{0.7}{\mathrm{In}}_{0.3}\mathrm{Te}$ appears to be driven by phonons, a proper understanding will require ideas beyond simple BCS theory.
- Published
- 2018
39. Ultralow-Temperature Thermal Conductivity of the Kitaev Honeycomb Magnet α−RuCl3 across the Field-Induced Phase Transition
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Shengqing Li, Jinsheng Wen, Yue Yu, Jinghui Wang, Yerong Xu, Y. Y. Huang, Kejing Ran, and J. M. Ni
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Phase transition ,Materials science ,Condensed matter physics ,Scattering ,Phonon ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic field ,Thermal conductivity ,Phase (matter) ,Magnet ,0103 physical sciences ,Quantum spin liquid ,010306 general physics ,0210 nano-technology - Abstract
Recently, there have been increasingly hot debates on whether there exists a quantum spin liquid in the Kitaev honeycomb magnet α-RuCl_{3} in a high magnetic field. To investigate this issue, we perform ultralow-temperature thermal conductivity measurements on single crystals of α-RuCl_{3} down to 80 mK and up to 9 T. Our experiments clearly show a field-induced phase transition occurring at μ_{0}H_{c}≈7.5 T, above which the magnetic order is completely suppressed. The minimum of thermal conductivity at 7.5 T is attributed to the strong scattering of phonons by magnetic fluctuations. Most importantly, above 7.5 T, we do not observe any significant contribution of thermal conductivity from gapless magnetic excitations, which puts a strong constraint on the nature of the high-field phase of α-RuCl_{3}.
- Published
- 2018
40. [Identification and application of Mycobacterium tuberculosis esxN-specific cell epitopes in the diagnosis of pulmonary tuberculosis]
- Author
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Zhigang, Xu, Dezhou, Li, Xinyu, Chen, Zhiliang, Duan, Jiayuan, Mao, and Jinsheng, Wen
- Subjects
Adult ,Antigens, Bacterial ,Interferon-gamma ,Mice ,Bacterial Proteins ,HLA-A2 Antigen ,Animals ,Epitopes, T-Lymphocyte ,Humans ,Middle Aged ,Tuberculosis, Pulmonary ,Aged ,T-Lymphocytes, Cytotoxic - Abstract
Objective To identify Mycobacterium tuberculosis ESAT-6 protein esxN-specific HLA-A*0201-restricted CTL epitopes and assess the diagnostic potential of the identified epitopes in pulmonary tuberculosis. Methods The esxN-specific HLA-A*0201-restricted CTL epitopes were predicted by the T epitope prediction software SYFPEITHI and further synthesized. The binding affinity of the candidate epitopes for HLA-A*0201 was detected using MHC-peptide complex stabilization assay. The immunogenicity of candidate epitopes were assessed using ELISPOT in HLA-A*0201 transgenic mice. Based on identified CTL epitopes, ESAT-6 and culture filtrate protein-10 (CFP-10), the ELISPOT was performed to detect the frequency of epitope/protein-specific CTL. Results In six CTL epitope candidates we tested, two epitopes, esxN
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- 2018
41. Gapless Spin Excitations in the Field-Induced Quantum Spin Liquid Phase of α−RuCl3
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Jinsheng Wen, Bruce Normand, Weiqiang Yu, Bin Liu, Kejing Ran, P. S. Wang, Tianrun Li, Zheng-Xin Liu, Jiacheng Zheng, and Jinghui Wang
- Subjects
Physics ,Quantum phase transition ,Field (physics) ,Condensed matter physics ,Plane (geometry) ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic field ,Gapless playback ,Phase (matter) ,0103 physical sciences ,Quantum spin liquid ,010306 general physics ,0210 nano-technology ,Spin-½ - Abstract
$\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ is a leading candidate material for the observation of physics related to the Kitaev quantum spin liquid (QSL). By combined susceptibility, specific-heat, and nuclear-magnetic-resonance measurements, we demonstrate that $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ undergoes a quantum phase transition to a QSL in a magnetic field of 7.5 T applied in the $ab$ plane. We show further that this high-field QSL phase has gapless spin excitations over a field range up to 16 T. This highly unconventional result, unknown in either Heisenberg or Kitaev magnets, offers insight essential to establishing the physics of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$.
- Published
- 2017
42. High-pressure magnetization and NMR studies of α−RuCl3
- Author
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Wenan Guo, Weiqiang Yu, Jinsheng Wen, Zheng-Xin Liu, Bin Liu, Jiacheng Zheng, Yi Cui, and Kejing Ran
- Subjects
Materials science ,Condensed matter physics ,Transition temperature ,Stacking ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetization ,Phase (matter) ,0103 physical sciences ,Volume fraction ,Orders of magnitude (data) ,010306 general physics ,0210 nano-technology ,Ground state ,Spin-½ - Abstract
We report high-pressure magnetization and $^{35}\mathrm{Cl}$ NMR studies on $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ with pressure up to 1.5 GPa. At low pressures, the magnetic ordering is identified by both the magnetization data and the NMR data, where the ${T}_{N}$ shows a concave shape dependence with pressure. These data suggest stacking rearrangement along the $c$ axis. With increasing pressure, phase separation appears prominently at $P\ensuremath{\ge}$ 0.45 GPa, and the magnetic volume fraction is completely suppressed at $P\ensuremath{\ge}$ 1.05 GPa. Meanwhile, a phase-transition-like behavior emerges at high pressures in the remaining volume by a sharp drop of magnetization $M(T)$ upon cooling, with the transition temperature ${T}_{x}$ increased to 250 K at 1 GPa. The $1{/}^{35}{T}_{1}$ is reduced by over three orders of magnitude when cooled below 100 K. This characterizes a high-pressure, low-temperature phase with nearly absent static susceptibility and low-energy spin fluctuations. The nature of the high-pressure ground state is discussed, where a magnetically disordered state is proposed as a candidate state.
- Published
- 2017
43. T Cell Immunity to Zika and Dengue Viral Infections
- Author
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Jinsheng Wen and Sujan Shresta
- Subjects
0301 basic medicine ,T cell ,Secondary infection ,viruses ,T-Lymphocytes ,Immunology ,Review ,Dengue virus ,medicine.disease_cause ,Zika virus ,Dengue fever ,Dengue ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Virology ,medicine ,Animals ,Humans ,Immunity, Cellular ,biology ,Sequence Homology, Amino Acid ,Zika Virus Infection ,Outbreak ,virus diseases ,Cell Biology ,Zika Virus ,biochemical phenomena, metabolism, and nutrition ,Dengue Virus ,biology.organism_classification ,medicine.disease ,Flavivirus ,030104 developmental biology ,medicine.anatomical_structure ,030215 immunology - Abstract
The 2015-2016 Zika virus (ZIKV) outbreak in the Americas has brought this relatively unknown flavivirus into the spotlight as the etiologic agent of congenital Zika syndrome in newborns and, potentially, of Guillain-Barre syndrome in adults. ZIKV shares a high degree of amino acid sequence homology with the closely related flavivirus Dengue virus (DENV). Due to the paucity of research investigating T cell-mediated immune responses to ZIKV, the precise roles of T cells in protection against and pathogenesis of ZIKV infection are unclear. Nevertheless, knowledge gained from studies of T cell responses to other flaviviruses, such as the four DENV serotypes, provides a framework for investigating and understanding anti-ZIKV T cell responses. In this review, we summarize our current understanding of how T cells respond to primary and secondary infections with DENV and ZIKV. A thorough understanding of the role of ZIKV-specific and DENV cross-reactive T cells in controlling infection is essential for developing ZIKV- and DENV-specific vaccines with maximal safety and efficacy.
- Published
- 2017
44. Magnetic neutron scattering studies on the Fe-based superconductor system Fe1+yTe1−xSex
- Author
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Jinsheng Wen
- Subjects
Superconductivity ,Physics ,Tetragonal crystal system ,Condensed matter physics ,Magnetism ,Condensed Matter::Superconductivity ,General Physics and Astronomy ,Antiferromagnetism ,Wave vector ,Neutron scattering ,Resonance (particle physics) ,Magnetic field - Abstract
I present a brief overview on the interplay between magnetism and superconductivity in one of the Fe-based superconductor systems, Fe 1 + y Te 1 − x Se x , where the research of our group has centered. The parent compound Fe 1 + y Te is an antiferromagnet; with Se doping, antiferromagnetic order is suppressed, followed by the appearance of superconductivity; optimal superconductivity is achieved when x ∼ 50 % , with a superconducting temperature T c of ∼ 15 K. The parent compound has an in-plane magnetic ordering wave vector around (0.5, 0) (using the tetragonal notation with two Fe atoms per cell). When Se concentration increases, the spectral weight appears to be shifted to the wave vector around (0.5, 0.5), accompanying the optimization of superconductivity. A neutron-spin resonance has been observed around (0.5, 0.5) below T c , and is suppressed, along with superconductivity, by an external magnetic field. Taking these evidences into account, it is concluded that magnetism and superconductivity in this system couple to each other closely—while the static magnetic order around (0.5, 0) competes with superconductivity, the spin excitations around (0.5, 0.5) may be an important ingredient for it. I will also discuss the nature of magnetism and substitution effects of 3 d transition metals.
- Published
- 2015
45. Identification of cytotoxic T lymphocyte epitopes in dengue virus serotype 1
- Author
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Xinyu Chen, Huifang Liu, Minghua Jiang, Jiang-Long Guo, Zhiliang Duan, Jinsheng Wen, and Xi Huang
- Subjects
viruses ,Immunogenicity ,ELISPOT ,virus diseases ,biochemical phenomena, metabolism, and nutrition ,Dengue virus ,Biology ,medicine.disease_cause ,Peripheral blood mononuclear cell ,Virology ,Molecular biology ,Epitope ,Infectious Diseases ,medicine ,Cytotoxic T cell ,Peptide sequence ,CD8 - Abstract
Dengue virus (DENV) has a serious and growing impact on global health and the exact role of DENV-specific CD8(+) T-cells in DENV infection is still uncertain. In the present study, SYFPEITHI algorithm was used to screen the amino acid sequence of Dengue virus serotype 1 (DENV-1) for potential epitopes, and seven putative HLA-A*1101-restricted and five putative HLA-A*2402-restricted epitopes conserved in hundreds of DENV-1 strains were synthesized. The binding affinity of these epitope candidates to corresponding HLA molecules was evaluated using competitive peptide-binding assay. The immunogenicity and specificity of peptides were further tested in HLA-A*1101 transgenic mice, HLA-A*2402 transgenic mice and peripheral blood mononuclear cells (PBMCs) of patients infected with DENV-1. Percentage inhibition (PI) values calculated in competitive peptide-binding assay showed that six peptides (E39-47 PTLDIELLK, NS5(505-513) GVEGEGLHK, NS2b(15-23) SILLSSLLK, NS5(561-569) ALLATSIFK, NS3(99-107) AVEPGKNPK, and NS4b(159-167) VVYDAKFEK) could bind to HLA-A*1101 molecule with high affinity and five peptides (NS3472-480 QYIYMGQPL, NS4a40-48 AYRHAMEEL, NS5(880-888) DYMTSMKRF, NS3(548-556) SYKVASEGF, and NS3(22-30) IYRILQRGL) have a high affinity for HLA-A*2402 molecule. Enzyme-linked immunospot (ELISPOT) results indicated that these high-affinity peptides were recognized by splenocytes of DENV-1-infected transgenic mice and high-affinity peptide-immunized transgenic mice displayed high levels of peptide-specific IFN-γ-secreting cells. In addition, both peptide-pulsed splenocytes and DENV-1-infected splenic monocytes were efficiently killed by these peptide-specific cytotoxic T lymphocytes. Finally, except NS2b(15-23), 10 high-affinity peptides were recognized by PBMCs of patients infected with DENV-1. These identified epitopes would contribute to the understanding of the function of DENV-specific CD8(+) T-cells.
- Published
- 2015
46. Identification of Mycobacterium tuberculosis PPE68-Specific HLA-A*0201-Restricted Epitopes for Tuberculosis Diagnosis
- Author
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Xi Huang, Huifang Liu, Jinsheng Wen, De-zhou Li, Bokun Chen, Zhiliang Duan, Xinyu Chen, Qiang Li, and Wang Sina
- Subjects
Enzyme-Linked Immunospot Assay ,Tuberculosis ,T-Lymphocytes ,Epitopes, T-Lymphocyte ,Mice, Transgenic ,Sensitivity and Specificity ,Applied Microbiology and Biotechnology ,Microbiology ,Peripheral blood mononuclear cell ,Epitope ,Mycobacterium tuberculosis ,Interferon-gamma ,Bacterial Proteins ,Tuberculosis diagnosis ,HLA-A2 Antigen ,medicine ,Animals ,Humans ,Interferon gamma ,biology ,ELISPOT ,General Medicine ,biology.organism_classification ,medicine.disease ,Virology ,Immunology ,Mycobacterium ,medicine.drug - Abstract
PPE68 is a Mycobacterium tuberculosis-specific protein which is absent from the vaccine strains of BCG. A panel of 14 PPE68-derived peptides predicted to bind to HLA-A*0201 was synthesized. The HLA-A*0201 restriction of these peptides was determined in T2 cell line and HLA-A*0201 transgenic mice. The specificity of peptides was assessed in pulmonary tuberculosis (TB) patients using IFN-γ enzyme-linked immunospot (ELISPOT) assay, and immunodominant peptides were further used to evaluate their diagnostic potential in HLA-A*0201-positive pulmonary TB patients. 13 out of 14 peptides were identified as high-affinity binders. Of these peptides, 12 peptides induced significant IFN-γ-secreting T cell response in transgenic mice and 9 peptides were efficiently recognized by peripheral blood mononuclear cells of 10 HLA-A*0201-positive TB patients. Four immunodominant HLA-A*0201-restricted epitopes (PPE68126-134, PPE68133-141, PPE68140-148, and PPE68148-156) were recognized by the most of 80 HLA-A*0201-positive TB patients (81, 86, 74, and 84 %, respectively). These epitopes may be used for a potential diagnosis of M. tuberculosis infection.
- Published
- 2015
47. Phase diagram of the relaxor ferroelectric (1 −x)Pb(Mg1/3Nb2/3)O3+xPbTiO3revisited: a neutron powder diffraction study of the relaxor skin effect
- Author
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Chris Stock, Jinsheng Wen, Daniel Phelan, Y Bing, Masato Matsuura, J Gao, Qingzhen Huang, Guangyong Xu, Peter M. Gehring, Efrain E. Rodriguez, and Z.-G. Ye
- Subjects
Diffraction ,Phase boundary ,Materials science ,Condensed matter physics ,X-ray crystallography ,Neutron diffraction ,General Materials Science ,Neutron scattering ,Instrumentation ,Powder diffraction ,Monoclinic crystal system ,Phase diagram - Abstract
We revisit the phase diagram of the relaxor ferroelectric PMN-xPT using neutron powder diffraction to test suggestions that residual oxygen vacancies and/or strain affect the ground state crystal structure. Powdered samples of PMN-xPT were prepared with nominal compositions of x=0.10, 0.20, 0.30, and 0.40 and divided into two identical sets, one of which was annealed in air to relieve grinding-induced strain and to promote an ideal oxygen stoichiometry. For a given composition and temperature the same structural phase is observed for each specimen. However, the distortions in all of the annealed samples are smaller than those in the as-prepared samples. Further, the diffraction patterns for x=0.10, 0.20, and 0.30 are best refined using the monoclinic Cm space group. By comparing our neutron diffraction results to those obtained on single crystals having similar compositions, we conclude that the relaxor skin effect in PMN-xPT vanishes on the Ti-rich side of the morphotropic phase boundary.
- Published
- 2015
48. Identification of conserved and HLA-A*2402-restricted epitopes in Dengue virus serotype 2
- Author
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De-zhou Li, Xi Huang, Bokun Chen, Xiao-Zhi Zhong, Zhiliang Duan, Huifang Liu, Xinyu Chen, Jinsheng Wen, Yang Jinlin, and Wang Sina
- Subjects
Serotype ,Cancer Research ,viruses ,Epitopes, T-Lymphocyte ,Mice, Transgenic ,Dengue virus ,Biology ,Serogroup ,medicine.disease_cause ,Peripheral blood mononuclear cell ,Epitope ,Cell Line ,Immunophenotyping ,Dengue ,Epitopes ,Immunity ,Virology ,medicine ,Splenocyte ,Animals ,Humans ,Amino Acid Sequence ,HLA-A Antigens ,virus diseases ,Dengue Virus ,Molecular biology ,HLA-A ,Disease Models, Animal ,Infectious Diseases ,Cytokines ,Female ,Immunization ,Peptides ,Epitope Mapping ,CD8 ,T-Lymphocytes, Cytotoxic - Abstract
In this study, we set out to identify dengue virus serotype 2 (DENV-2)-specific HLA-A*2402-restricted epitopes and determine the characteristics of T cells generated to these epitopes. We screened the full-length amino-acid sequence of DENV-2 to find potential epitopes using the SYFPEITHI algorithm. Twelve putative HLA-A*2402-binding peptides conserved in hundreds of DENV-2 strains were synthesized, and the HLA restriction of peptides was tested in HLA-A*2402 transgenic mice. Nine peptides (NS4b(228-237), NS2a(73-81), E(298-306), M(141-149), NS4a(96-105), NS4b(159-168), NS5(475-484), NS1(162-171), and NS5(611-620)) induced high levels of peptide-specific IFN-γ-secreting cells in HLA-A*2402 transgenic mice. Apart from IFN-γ, NS4b(228-237-), NS2a(73-81-) and E(298-306)-specific CD8(+) cells produced TNF-α and IL-6 simultaneously, whereas M(141-149-) and NS5(475-484-) CD8(+) cells produced only IL-6. Moreover, splenic mononuclear cells (SMCs) efficiently recognized and killed peptide-pulsed splenocytes. Furthermore, each of nine peptides could be recognized by splenocytes from DENV-2-infected HLA-A*2402 transgenic mice. The SMCs from HLA-A*2402 transgenic mice immunized with nine immunogenic peptides efficiently killed DENV-2-infected splenic monocytes. The present identified epitopes have the potential to be new diagnostic tools for characterization of T-cell immunity in DENV infection and may serve as part of a universal epitope-based vaccine.
- Published
- 2015
49. MicroRNA-155 induction by Mycobacterium bovis BCG enhances ROS production through targeting SHIP1
- Author
-
Xi Huang, Miao Li, Jinsheng Wen, Jinli Wang, Xiaoxia Zhan, Kun Yang, Minhao Wu, Meiyu Li, and Lianqiang Feng
- Subjects
MAP Kinase Signaling System ,Immunology ,Biology ,Nitric oxide ,Mice ,chemistry.chemical_compound ,Immune system ,Downregulation and upregulation ,Animals ,Tuberculosis ,Molecular Biology ,Cells, Cultured ,Reactive nitrogen species ,Mice, Knockout ,chemistry.chemical_classification ,Reactive oxygen species ,Inositol Polyphosphate 5-Phosphatases ,NF-kappa B ,Mycobacterium bovis ,Reactive Nitrogen Species ,Phosphoric Monoester Hydrolases ,Toll-Like Receptor 2 ,Up-Regulation ,Cell biology ,Mice, Inbred C57BL ,Nitric oxide synthase ,MicroRNAs ,TLR2 ,chemistry ,Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases ,Macrophages, Peritoneal ,biology.protein ,Signal transduction ,Reactive Oxygen Species - Abstract
Macrophages play a critical role in the host immune response against mycobacterial infection. Our previous study has demonstrated that microRNA-155 (miR-155), one of the most important small non-coding RNAs in the immune system, promotes oxygen-independent mycobacterial killing in macrophages. However, little is known regarding the role of miR-155 in modulating oxygen-dependent mycobactericidal response in macrophages, including the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). In the present study, we demonstrated that miR-155 was increased in macrophages after Mycobacterium bovis bacille Calmette-Guérin (BCG) infection. Moreover, the BCG-induced upregulation of miR-155 in macrophages was dependent on TLR2, NF-κB and JNK signaling pathways. More importantly, our study explored that miR-155 significantly elevated ROS production in macrophages, although miR-155 had no influence on the inducible nitric oxide synthase (iNOS) expression or nitric oxide (NO) production. In addition, our study demonstrated that miR-155 repressed the expression of src homology 2 (SH2) containing inositol 5-phosphatase1 (SHIP1), and knockdown of SHIP1 greatly increased ROS production in BCG-infected macrophages. Collectively, these data indicate that miR-155 modulates ROS but not RNS production by targeting SHIP1, which may provide a better understanding of the host anti-mycobacterial response.
- Published
- 2014
50. Surprising loss of three-dimensionality in low-energy spin correlations on approaching superconductivity in Fe1+yTe1−xSex
- Author
-
Barry Winn, Yang Zhao, Genda Gu, Robert J. Birgeneau, Garrett E. Granroth, Igor Zaliznyak, Zhijun Nmn Xu, Guangyong Nmn Xu, John M. Tranquada, Jinsheng Wen, and J. Schneeloch
- Subjects
Physics ,Superconductivity ,Condensed matter physics ,Magnetism ,02 engineering and technology ,Neutron scattering ,021001 nanoscience & nanotechnology ,01 natural sciences ,Omega ,Inelastic neutron scattering ,Pairing ,0103 physical sciences ,Quantum spin liquid ,010306 general physics ,0210 nano-technology ,Spin-½ - Abstract
We report inelastic neutron scattering measurements of low-energy ($\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\lesssim}10$ meV) magnetic excitations in the ``11'' system ${\mathrm{Fe}}_{1+y}{\mathrm{Te}}_{1\ensuremath{-}x}{\mathrm{Se}}_{x}$. The spin correlations are two-dimensional (2D) in the superconducting samples at low temperature, but appear much more three-dimensional (3D) when the temperature rises well above ${T}_{c}\ensuremath{\sim}15$ K, with a clear increase of the (dynamic) spin correlation length perpendicular to the Fe planes. This behavior is extremely unusual; typically, the suppression of thermal fluctuations at low temperature would favor the enhancement of 3D correlations, or even ordering, and the reversion to 2D cannot be naturally explained when only the spin degree of freedom is considered. Our results suggest that the low temperature physics in the 11 system, in particular the evolution of low-energy spin excitations towards superconducting pairing, intrinsically involves changes in orbital correlations.
- Published
- 2017
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