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10 results on '"Huifei Zhai"'

1. Transport anomalies in the layered compound BaPt4Se6

Author

Sheng Li, Yichen Zhang, Hanlin Wu, Huifei Zhai, Wenhao Liu, Daniel Peirano Petit, Ji Seop Oh, Jonathan Denlinger, Gregory T. McCandless, Julia Y. Chan, Robert J. Birgeneau, Gang Li, Ming Yi, and Bing Lv

Subjects
Materials of engineering and construction. Mechanics of materials, TA401-492, Atomic physics. Constitution and properties of matter, QC170-197
Abstract

Abstract We report a layered ternary selenide BaPt4Se6 featuring sesqui-selenide Pt2Se3 layers sandwiched by Ba atoms. The Pt2Se3 layers in this compound can be derived from the Dirac-semimetal PtSe2 phase with Se vacancies that form a honeycomb structure. This structure results in a Pt (VI) and Pt (II) mixed-valence compound with both PtSe6 octahedra and PtSe4 square net coordination configurations. Temperature-dependent electrical transport measurements suggest two distinct anomalies: a resistivity crossover, mimic to the metal-insulator (M-I) transition at ~150 K, and a resistivity plateau at temperatures below 10 K. The resistivity crossover is not associated with any structural, magnetic, or charge order modulated phase transitions. Magnetoresistivity, Hall, and heat capacity measurements concurrently suggest an existing hidden state below 5 K in this system. Angle-resolved photoemission spectroscopy measurements reveal a metallic state and no dramatic reconstruction of the electronic structure up to 200 K.

Published
2021
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2. The Stoichiometry of TCNQ-Based Organic Charge-Transfer Cocrystals

Author

Jiaoyang Gao, Huifei Zhai, Peng Hu, and Hui Jiang

Subjects
single crystals, organic semiconductors, charge transfer cocrystals, the degree of charge transfer, conductivity, mobility, Crystallography, QD901-999
Abstract

Organic charge-transfer cocrystals (CTCs) have attracted significant research attention due to their wide range of potential applications in organic optoelectronic devices, organic magnetic devices, organic energy devices, pharmaceutical industry, etc. The physical properties of organic charge transfer cocrystals can be tuned not only by changing the donor and acceptor molecules, but also by varying the stoichiometry between the donor and the acceptor. However, the importance of the stoichiometry on tuning the properties of CTCs has still been underestimated. In this review, single-crystal growth methods of organic CTCs with different stoichiometries are first introduced, and their physical properties, including the degree of charge transfer, electrical conductivity, and field-effect mobility, are then discussed. Finally, a perspective of this research direction is provided to give the readers a general understanding of the concept.

Published
2020
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3. Post cobalt doping and defect engineering of NbSSe for efficient hydrogen evolution reaction

Author

Yuxin Ren, Xiaoyan Miao, Jiaxiang Zhang, Qidong Lu, Yi Chen, Haibo Fan, Feng Teng, Huifei Zhai, Xuexia He, Yi Long, Chunmei Zhang, and Peng Hu

Subjects
Renewable Energy, Sustainability and the Environment, General Materials Science, General Chemistry
Abstract

Post cobalt doped NbSSe was synthesized by combining chemical vapor transport and the hydrothermal method, which exhibited excellent HER performance due to the synergistic effect of cobalt doping and S/Se vacancies.

Published
2023

4. Bulk superconductivity in transition metal oxide TaO

Author

Ziyang Zhang, Zi Wang, Xiangfei Dai, Yudi Chen, Shaodong Lai, Feng Qin, Xuan Zhou, Chunxiang Wu, Hangdong Wang, Jinhu Yang, Bin Chen, Huifei Zhai, Yun Zhou, Miaogen Chen, Jianhua Du, Zhiwei Jiao, and Minghu Fang

Subjects
Energy Engineering and Power Technology, Electrical and Electronic Engineering, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
Published
2023

5. Crystal Structure and Electronic Properties of New Compound Zr6.5Pt6Se19

Author

Hanlin Wu, Huifei Zhai, Gregory T. McCandless, Sheng Li, Julia Y. Chan, Maurice Sorolla, Daniel Peirano Petit, and Bing Lv

Subjects
Inorganic Chemistry, Crystallography, chemistry.chemical_compound, Transition metal, Chemistry, Chalcogenide, Crystal structure, Structure type, Physical and Theoretical Chemistry, Ternary operation, Electronic properties
Abstract

A new ternary nonstoichiometric Zr6.5Pt6Se19 has been discovered as a part of effort to dope Zr into the layered transitional metal chalcogenide PtSe2. With a new structure type (oC68), it is the f...

Published
2020

6. Synthesis and Structure of a Nonstoichiometric Zr3.55Pt4Sb4 Compound

Author

Maurice Sorolla, Hanlin Wu, Gregory T. McCandless, Xiaoyuan Liu, Julia Y. Chan, Sheng Li, Bing Lv, and Huifei Zhai

Subjects
010405 organic chemistry, Chemistry, Fermi level, Electronic structure, Crystal structure, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Crystallography, symbols.namesake, Chemical bond, Antimonide, symbols, Physical and Theoretical Chemistry, Ternary operation, Pseudogap, Electronic band structure
Abstract

A nonstoichiometric ternary antimonide, Zr3.55Pt4Sb4, with a new structure type (hP24), has been synthesized via arc-melting. Its crystal structure was determined by single-crystal X-ray diffraction with hexagonal space group P63/mmc and lattice parameters a = 4.391(3) A, c = 30.53(2) A, and V = 509.7(8) A3. It features the unique Pt4Sb4 slab with Pt-Pt bonds and is reminiscent to hexagonal diamond substructures. Three different Zr atoms, occupying three different sites, aid in the close-packing of the Pt and Sb atoms. Electronic structure calculations show the half occupancy of one Zr site creates a pseudogap at the Fermi level and optimizes the Pt-Sb bonding interactions. This enhances the electronic stability and accounts for the very narrow phase width observed for this nonstoichiometric compound. Furthermore, strong Zr-Pt and Zr-Sb interactions play a crucial role in the chemical bonding of the title compound. Electrical transport measurements show metallic behavior of this compound down to 2 K, consistent with the band structure calculations.

Published
2019

7. Synthesis and Structure of a Nonstoichiometric Zr

Author

Sheng, Li, Xiaoyuan, Liu, Maurice, Sorolla, Gregory T, McCandless, Hanlin, Wu, Huifei, Zhai, Julia Y, Chan, and Bing, Lv

Abstract

A nonstoichiometric ternary antimonide, Zr

Published
2019

8. The Stoichiometry of TCNQ-Based Organic Charge-Transfer Cocrystals

Author

Peng Hu, Jiaoyang Gao, Huifei Zhai, Hui Jiang, and School of Materials Science and Engineering

Subjects
Materials science, General Chemical Engineering, 02 engineering and technology, Organic Semiconductors, Conductivity, 010402 general chemistry, single crystals, 01 natural sciences, Inorganic Chemistry, Electrical resistivity and conductivity, lcsh:QD901-999, Molecule, General Materials Science, organic semiconductors, Range (particle radiation), Single Crystals, the degree of charge transfer, Materials [Engineering], Charge (physics), charge transfer cocrystals, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Acceptor, mobility, 0104 chemical sciences, Organic semiconductor, Chemical physics, conductivity, lcsh:Crystallography, 0210 nano-technology, Stoichiometry
Abstract

Organic charge-transfer cocrystals (CTCs) have attracted significant research attention due to their wide range of potential applications in organic optoelectronic devices, organic magnetic devices, organic energy devices, pharmaceutical industry, etc. The physical properties of organic charge transfer cocrystals can be tuned not only by changing the donor and acceptor molecules, but also by varying the stoichiometry between the donor and the acceptor. However, the importance of the stoichiometry on tuning the properties of CTCs has still been underestimated. In this review, single-crystal growth methods of organic CTCs with different stoichiometries are first introduced, and their physical properties, including the degree of charge transfer, electrical conductivity, and field-effect mobility, are then discussed. Finally, a perspective of this research direction is provided to give the readers a general understanding of the concept. National Research Foundation (NRF) Published version This research was funded by the National Natural Science Foundation of China (No. 51803168) and the APC was funded by Nowthwest University. P.H. also acknowledges financial support from the Youth Innovation Team of Shaanxi Universities. H.Z. acknowledges financial support from the National Natural Science Foundation of China (11704311), Natural Science Foundation of Shaanxi Provincial Department of Education (17JK0772) and Natural Science Foundation of Shaanxi Province (2018JQ1069). H.J. acknowledges the grants from the National Research Foundation, Prime Minister’s Office, Singapore under its Campus of Research Excellence and Technological Enterprise (CREATE) programme.

Published
2020

9. Role of valence changes and nanoscale atomic displacements in BiS2-based superconductors

Author

Jie Cheng, Huifei Zhai, Yu Wang, Guanghan Cao, Wei Xu, and Shengli Liu

Subjects
Superconductivity, X-ray absorption spectroscopy, Multidisciplinary, Valence (chemistry), Materials science, Strongly Correlated Electrons (cond-mat.str-el), Condensed matter physics, Extended X-ray absorption fine structure, Absorption spectroscopy, Doping, FOS: Physical sciences, 02 engineering and technology, Crystal structure, 021001 nanoscience & nanotechnology, 01 natural sciences, Condensed Matter - Strongly Correlated Electrons, Condensed Matter::Superconductivity, 0103 physical sciences, 010306 general physics, 0210 nano-technology, Nanoscopic scale
Abstract

Superconductivity within layered crystal structures has attracted sustained interest among condensed matter community, primarily due to their exotic superconducting properties. EuBiS2F is a newly discovered member in the BiS2-based superconducting family, which shows superconductivity at 0.3 K without extrinsic doping. With 50 at.% Ce substitution for Eu, superconductivity is enhanced with Tc increased up to 2.2 K. However, the mechanisms for the Tc enhancement have not yet been elucidated. In this study, the Ce-doping effect on the self-electron-doped superconductor EuBiS2F was investigated by X-ray absorption spectroscopy (XAS). We have established a relationship between Ce-doping and the Tc enhancement in terms of Eu valence changes and nanoscale atomic displacements. The new finding sheds light on the interplay among superconductivity, charge and local structure in BiS2-based superconductors., Comment: Accepted by Scientific Reports. 14 pages, 4 Figures

Published
2016

10. Coexistence of superconductivity and ferromagnetism in Sr0.5Ce0.5FBiS2.

Author

Lin Li, Yuke Li, Yuefeng Jin, Haoran Huang, Bin Chen, Xiaofeng Xu, Jianhui Dai, Li Zhang, Xiaojun Yang, Huifei Zhai, Guanghan Cao, and Zhuan Xu

Subjects
*X-ray diffraction, *MAGNETIC susceptibility, *FERROMAGNETIC materials, *ELECTRIC conductivity, *PHOTOCONDUCTIVITY
Abstract

Through the combination of x-ray diffraction, electrical transport, magnetic susceptibility, and heat capacity measurements, we studied the effect of Ce doping in the newly discovered SrFBiS2 system. It is found that Sr0.5Ce0.5FBiS2 undergoes a second-order transition below ∼7.5 K, followed by a superconducting transition with the critical temperature Tc∼2.8 K. Our transport, specific heat, and dc-magnetization results suggest the presence of bulk ferromagnetic correlation of Ce ions below 7.5 K that coexist with superconductivity when the temperature is further lowered below 2.8 K. [ABSTRACT FROM AUTHOR]

Published
2015
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