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We report a possible coexistence of nontrivial topology and antiferromagnetism in the newly discovered compounds EuCdBi2, with magnetic Eu layer locating above and below Bi square net. The X-ray diffraction on single crystals and powder indicats that this 112-type material crystalizes in space group of I4/mmm, the same as SrMnBi2 and EuMnBi2. Our combined measurements of magnetization, electrical transport and specific heat consistently reveal antiferromagnetic (AFM) transition of Eu2+ moments at TN = 20 K. The Eu moments are not saturated under a field of 7 T at 1.8 K. The anisotropic susceptibility suggests the Eu moments lie in the ab plane, and a metamagnetic (MM) transition is observed near 1 T below TN. Large positive magnetoresistance (MR) present for both H‖ab and H‖c, which are considered to contain part contributions from Dirac bands. Hall measurements show the electron-hole compensation effect is prominent above 100 K, with a crossover of Hall resistance from negative to positive values at ∼150 K. The fitted mobility of electrons is as high as 3250 cm2 V−1 S−1 at 1.8 K. Interestingly, the rapid increase of carrier density and suppression of mobility appear at around TN, indicating non-negligible interaction between Eu moments and electron/hole bands. EuCdBi2 may provide a new platform to investigate the interplay of topological bands and antiferromagnetic order.

The structure of a 4,4′-dinitrobiphenyl and biphenyl 3 : 1 composite cocrystal is presented in (3 + 1)D superspace.

We report a new polymorph of LuRuGe, obtained in indium flux. This phase exhibits the noncentrosymmetric ZrNiAl-type structure with the space group P62m as determined by single-crystal X-ray diffraction. This polymorph can convert into another centrosymmetric polymorph (TiNiSi-type structure, space group Pnma) at high temperatures. We performed electrical transport, magnetization, and specific heat measurements on this new phase. It shows metallic behavior with a Hall sign change from negative at 2 K to positive at 125 K. LuRuGe exhibits Pauli paramagnetism as the ground state with no local magnetic moments from either the Ru or Lu site. The Debye temperature Θ = 348 K and electronic coefficient γe = 3.6 mJ K-2 mol-1 are extracted from the low-temperature specific heat data in LuRuGe. We also carried out first-principles density functional theory calculations to map out the electronic band structure and density of states. There are several electronic bands crossing the Fermi level, supporting a multiband scenario consistent with the Hall sign change. The density of states around the Fermi level is mainly from Ru 4d and Ge 4p electrons, indicating a strong hybridization between those atomic orbitals.

Three Keggin polyoxotungstate inorganic–organic hybrid compounds have been synthesized under hydrothermal conditions by using H4SiW12O40 as starting materials: [{CuII(2,2′-bipy)2}2SiW12O40]·2H2O (1), [{CuII(phen)2}2SiW12O40] (2) and [{CuI(2,2′-bipy)2}4SiW12O40] (3) (2,2′-bipy = 2,2′-bipyridine, phen = 1,10′-phenanthroline) and structurally characterized by elemental analysis, IR spectra, TG analysis and X-ray single-crystal diffraction. Three compounds are all based on [SiW12O40]4− α-Keggin type building block and synthesized under the same reaction condition, only different compound 1 and 2 ligand, 1 and 3 pH value. Compound 1 displays a novel example of two-dimensional framework with tetra-supporting α-Keggin polyanions which are linked by four same fragments and it becomes 3D structure due to the existence of hydrogen bonds. Compound 2 shows that the bi-supporting polyoxotungstate molecule consists of a α-Keggin polyoxoanion [SiW12O40]4− and a pair of transition metal complex fragments which are covalently linked to opposite sides of the surface terminal oxygen atoms of WO6 octahedra. Compound 3 consists of α-[SiW12O40]4− polyoxoanions, counter cations [Cu(2,2′-bipy)2]+. The crystal packing is stabilized by H-bonds and weak π–π interactions, leads to a 3D supramolecular architecture. The results show that the pH value of the reaction system plays a crucial role in structural control of self-assembled processes. The thermal stabilities of the compounds are discussed. Three Keggin polyoxotungstate inorganic–organic hybrid compounds have been synthesized under hydrothermal conditions by using H4SiW12O40 as starting materials: [{CuII(2,2′-bipy)2}2SiW12O40]·2H2O (1), [{CuII(phen)2}2SiW12O40] (2) and [{CuI(2,2′-bipy)2}4SiW12O40] (3) (2,2′-bipy = 2,2′-bipyridine, phen = 1,10′-phenanthroline) and structurally characterized by elemental analysis, IR spectra, TG analysis and X-ray single-crystal diffraction. Three compounds are all based on [SiW12O40]4− α-Keggin type building block and synthesized under the same reaction condition, only different compound 1 and 2 ligand, 1 and 3 pH value.

The SnO2/Li4Ti5O12/C compound was gained via hydrothermal, sintering, and ball milling methods. Nano-grained SnO2/Li4Ti5O12 are homogeneously wrapped in a sheet-like graphite. Li4Ti5O12 possesses cyclic stability and superior rate capacity. Meanwhile, the SnO2/Li4Ti5O12 hybrid can supply abundant active sites for absorption of Li+, mitigate chemical stress in cycling, and prevent the ultrathin graphite nanosheets from stacking. Besides, the sheet-like graphite could reduce volume variation in cycling and reduce transmission distance for the electron or Li+. Therefore, an outstanding electrochemical property of the SnO2/Li4Ti5O12/C composite can be obtained.

A new ternary Mo-SnO2-graphite composite has been constructed via hydrothermal and ball milling. The Mo/SnO2 hybrids were homogeneously dispersed in graphite nanosheets. In the Mo-SnO2-graphite, Mo can inhibit the Sn nanoparticle aggregation, enhance the reversible conversion reaction in lithiation, and improve the electrochemical performance. Consequently, the Mo-SnO2-graphite composite contributes a high capacity of 1317.4 mAh g-1 at 0.2 A g-1 after 200 cycles, remarkable rate property of 514.0 mAh g-1 at 5 A g-1, and long-term cyclic stabilization of 759.0 mAh g-1 after 950 cycles at 1.0 A g-1. With outstanding electrochemical performance and facial synthesis, the ternary Mo-SnO2-graphite is a hopeful anode material for lithium-ion batteries (LIBs).

We report pressure-induced superconductivity in a ternary and nonmagnetic Cu-containing semiconductor, Cu2Br2Se6, with a wide band gap of 1.89 eV, in which the Cu and Br atoms generate infinite 21 ...

Halide perovskites are anticipated to impact next generation high performance solar cells because of their extraordinary charge transport and optoelectronic properties. However, their thermal transport behavior has received limited attention. In this work, we studied the thermal transport and thermoelectric properties of the CsSnBr3-xIx perovskites. We find a strong correlation between lattice dynamics and an ultralow thermal conductivity for series CsSnBr3-xIx reaching 0.32 Wm-1K-1 at 550 K. The CsSnBr3-xIx also possess a decent Seebeck coefficient and controllable electrical transport properties. The crystallography data and theoretical calculations suggest the Cs atom deviates from its ideal cuboctahedral geometry imposed by the perovskite cage and behaves as a heavy atom rattling oscillator. This off-center tendency of Cs, together with the distortion of SnX6 (X = Br or I) octahedra, produces a highly dynamic and disordered structure in CsSnBr3-xIx, which gives rise to a very low Debye temperature and phonon velocity. Moreover, the low temperature heat capacity data suggests strong coupling between the low frequency optical phonons and heat carrying acoustical phonons. This induces strong phonon resonance scattering that induces the ultralow lattice thermal conductivity of CsSnBr3-xIx.

IUCrJ 9(3), 378 - 385 (2022). doi:10.1107/S2052252522003888, EuAl4 possesses the BaAl$_4$ crystal structure type with tetragonal symmetry I4/mmm. It undergoes a charge density wave (CDW) transition at T$_{CDW}$ = 145 K and features four consecutive antiferromagnetic phase transitions below 16 K. Here we use single-crystal X-ray diffraction to determine the incommensurately modulated crystal structure of EuAl$_4$ in its CDW state. The CDW is shown to be incommensurate with modulation wave vector $q$ = (0,0,0.1781 (3)) at 70 K. The symmetry of the incommensurately modulated crystal structure is orthorhombic with superspace group Fmmm(00σ)s00, where Fmmm is a subgroup of I4/mmm of index 2. Both the lattice and the atomic coordinates of the basic structure remain tetragonal. Symmetry breaking is entirely due to the modulation wave, where atoms Eu and Al1 have displacements exclusively along a, while the fourfold rotation would require equal displacement amplitudes along a and b. The calculated band structure of the basic structure and interatomic distances in the modulated crystal structure both indicate the Al atoms as the location of the CDW. The tem­per­ature dependence of the specific heat reveals an anomaly at T$_{CDW}$ = 145 K of a magnitude similar to canonical CDW systems. The present discovery of orthorhombic symmetry for the CDW state of EuAl$_4$ leads to the suggestion of monoclinic instead of orthorhombic symmetry for the third AFM state., Published by Chester

C26H24N3O3SAg, monoclinic, P21/c (no. 14), a = 13.1936(9) Å, b = 11.0544(7) Å, c = 16.3653(9) Å, β = 99.214(6)°, V = 2356.0(3) Å3, Z = 4, R gt(F) = 0.0495, wR ref(F 2) = 0.1080, T = 293(2) K.

C40H42Mo5N8O23P2, triclinic, P1̄ (no. 2), a = 10.9867(2) Å, b = 15.4753(3) Å, c = 15.5666(3) Å, α = 85.583(2)°, β = 81.294(2)°, γ = 84.844(2)°, V = 2600.18(9) Å3, Z = 2, R gt(F) = 0.0208, wR ref(F 2) = 0.0485, T = 293(2) K.

C44H44Ag2N6O8S2, triclinic, P1̄ (no. 2), a = 11.3967(5) Å, b = 12.6953(6) Å, c = 14.9539(7) Å, α = 80.903(4)°, β = 89.801(4)°, γ = 83.911(4)°, V = 2124.14(17) Å3, Z = 2, Rgt (F) = 0.0421, wR ref(F 2) = 0.1130, T = 293(2) K.

C36H52Ag2N10O8S2, orthorhombic, Pna21 (no. 33), a = 11.7911(16) Å, b = 31.310(5) Å, c = 10.6883(11) Å, V = 3945.9(9) Å3, Z = 4, R gt(F) = 0.0353, wR ref(F 2) = 0.0784, T = 293(2) K.

Quasi-one-dimensional (Q1D) structures comprising a compact array of indefinitely long 1D nanowires (NWs) are scarce, especially in a bulk device-scale showing metallic and semiconducting behaviors...

The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report...

Three kinds of composite coatings with different proportion of preplaced Ni-Mo-Si powders were fabricated on Ti6Al4V alloy by laser depositing to enhance the high temperature oxidation resistance. The microstructures of composite coatings were studied by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The microhardness of composite coatings was measured by Vickers microhardness tester. The samples of composite coatings and Ti6Al4V alloy underwent isothermal oxidation tests at 800 °C, and the oxidation mechanism was analyzed by thermodynamics and kinetics. Results indicate that composite coatings mainly include Ti5Si3, MoSi2 and Mo5Si3 as enhanced phases and α-Ti/NiTi as matrix, and have metallurgical bonding with substrate. With the increase of Ni content in composite coatings, the inter-metallic compounds α-Ti/NiTi matrix increased and the hard phase Ti5Si3 refined. The average microhardness of composite coatings is 2.6, 2.4, 2.3 times of that of Ti6Al4V alloy, respectively. Oxidation mass gain of the coatings are 5.6%, 12% and 57.9% of that of the substrate at 800 °C for 100 h, respectively, and oxide scales of the coatings are continuous and dense, showing good oxidation resistance at high temperatures.

The steam gasification of tableted biomass for H2 production in molten salts was investigated under different conditions. The results showed that the ternary molten carbonates (32 wt% Li2CO3, 33 wt% Na2CO3 and 35 wt% K2CO3) acted as heat medium and catalyst in the gasification process. The use of molten salts could significantly increase total gas and H2 production and simultaneously decrease the concentrations of CO and CH4 in the product gas, and also decrease the yield of condensable tar. The increase in gasification temperature and mass ratio of steam to biomass (S/B) was beneficial for H2 production process. However, excessive steam contributed slightly to the increase in H2 production and largely increased the energy consumption. The optimal S/B ratio was found to be 1.0. The feedstock after tabletting could completely immersed in molten salts, which improved the contact between biomass and molten salts and thus favored the biomass gasification for H2 production. When biomass particle size was 0.25 g/piece, the yield of H2 reached 807.53 mL/g biomass.

We report the two-dimensional (2D) natural heterostructure [Pb3.1Sb0.9S4][Au xTe2- x] ( x = 0.52-0.36) which shows anomalous, transverse nonsaturating negative magnetoresistance (MR). For x = 0.52, the material has a commensurately modulated structure with alternating [Pb3.1Sb0.9S4] rocksalt layers and atomically thin [Au xTe2- x] sheets, as determined by single-crystal X-ray diffraction using a (3 + 1)-dimensional space group; for other x compositions, the modulated structure is absent and the Au and Te atoms are disordered. The transport properties in this system at low temperature (

In this Letter, we describe quantitative magnetic imaging of superconducting vortices in RbEuFe_{4}As_{4} in order to investigate the unique interplay between the magnetic and superconducting sublattices. Our scanning Hall microscopy data reveal a pronounced suppression of the superfluid density near the magnetic ordering temperature in good qualitative agreement with a recently developed model describing the suppression of superconductivity by correlated magnetic fluctuations. These results indicate a pronounced exchange interaction between the superconducting and magnetic subsystems in RbEuFe_{4}As_{4}, with important implications for future investigations of physical phenomena arising from the interplay between them.

C25H29Ag2N5O9S, monoclinic, P21/m (no. 11), a = 8.5437(16) Å, b = 17.852(4) Å, c = 9.3335(13) Å, β = 101.380(16)°, V = 1395.6(5) Å3, Z = 2, R gt (F) = 0.0271, wR ref (F 2) = 0.0653, T = 293(2) K.

A friendly coexistence of superconductivity and magnetism is quite an unusual physical phenomenon. However, the authors find that in the new high-T${}_{c}$ magnetic superconductor RbEuFe${}_{4}$As${}_{4}$ the magnetic and superconducting subsystems show a remarkable cooperative response. In the external magnetic field, the magnetic Eu sublattice acts as an internal pump of the magnetic flux, while the superconducting component works as a valve controlling the flux entry through the pinning of flux-carrying Abrikosov vortices and establishes the self-organized critical state.

We investigate the effect of Ni doping on the Fe site in single crystals of the magnetic superconductor $\mathrm{Rb}\mathrm{Eu}{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}$ for doping concentrations of up to 4%. A clear suppression in the superconducting transition temperature is observed in specific-heat, resistivity, and magnetization measurements. Upon Ni doping, the resistivity curves shift up in a parallel fashion, indicating a strong increase of the residual resistivity due to scattering by charged dopant atoms while the shape of the curve and thus the electronic structure appear largely unchanged. The observed step $\mathrm{\ensuremath{\Delta}}C/{T}_{c}$ at the superconducting transition decreases strongly for increasing Ni doping in agreement with expectations based on a model of multiband superconductivity and strong interband pairing. The upper critical field slopes are reduced upon Ni doping for in-plane as well as out-of-plane fields, leading to a small reduction in the superconducting anisotropy. The specific-heat measurements of the magnetic transition reveal the same Berezinskii-Kosterlitz-Thouless behavior close to the transition temperature ${T}_{m}$ for all doping levels. The transition temperature is essentially unchanged upon doping. The in-plane to out-of-plane anisotropy of Eu magnetism observed at small magnetic fields is unaltered as compared to the undoped compound. All of these observations indicate a decoupling of the Eu magnetism from superconductivity and essentially no influence of Ni doping on the Eu magnetism in this compound.

Layered heterostructure materials with two different functional building blocks can teach us about emergent physical properties and phenomena arising from interactions between the layers. We report the intergrowth compounds KLa$M$$_{1-x}$Te$_{4}$ ($M$ = Mn, Zn; $x\approx$ 0.35) featuring two chemically distinct alternating layers [LaTe$_3$] and [K$M$$_{1-x}$Te]. Their crystal structures are incommensurate, determined by single X-ray diffraction for the Mn compound and transmission electron microscope (TEM) study for the Zn compound. KLaMn$_{1-x}$Te$_{4}$ crystallizes in the orthorhombic superspace group $Pmnm$(01/2${\gamma}$)$s$00 with lattice parameters $a$ = 4.4815(3) {\AA}, $b$ = 21.6649(16) {\AA} and $c$ = 4.5220(3) {\AA}. It exhibits charge density wave (CDW) order at room temperature with a modulation wave vector $\mathbf{q}$ = 1/2$\mathbf{b}$* + 0.3478$\mathbf{c}$* originating from electronic instability of Te-square nets in [LaTe$_{3}$] layers. The Mn analog exhibits a cluster spin glass behavior with spin freezing temperature $T_{\mathrm{f}}$ $\approx$ 5 K attributed to disordered Mn vacancies and competing magnetic interactions in the [Mn$_{1-x}$Te] layers. The Zn analog also has charge density wave order at room temperature with a similar $\mathbf{q}$-vector having the $\mathbf{c}$* component ~ 0.346 confirmed by selected-area electron diffraction (SAED). Electron transfer from [K$M_{1-x}$Te] to [LaTe$_{3}$] layers exists in KLa$M_{1-x}$Te$_{4}$, leading to an enhanced electronic specific heat coefficient. The resistivities of KLa$M_{1-x}$Te$_{4}$ ($M$ = Mn, Zn) exhibit metallic behavior at high temperatures and an upturn at low temperatures, suggesting partial localization of carriers in the [LaTe$_{3}$] layers with some degree of disorder associated with the $M$ atom vacancies in the [$M_{1-x}$Te] layers., Comment: 1 table, 10 figures, 35 pages

The monoclinic narrow-gap (∼0.08 eV) semiconductor CsBi4Te6 is a unique layered system which can be doped to achieve high thermoelectric performance as well as superconductivity. Here, we report superconductivity and structure change induced by alloying CsBi4Te6 single crystals with Na and K. Substitution of Na in CsBi4Te6 with doping levels ≥0.39 and of K with ≥0.63 transforms the original monoclinic structure (p-type) to the orthorhombic RbBi3.67Te6-type structure (n-type). When the K level is ≤0.18, the monoclinic structure type of CsBi4Te6 is retained. Transport and magnetic measurements on all as-synthesized doped single crystals demonstrate type-II, bulk superconductivity. A maximal superconducting transition at 5.07 K, which is the highest temperature in bismuth chalcogenide-based superconductors, was obtained in Cs0.82K0.18Bi4Te6 with a high upper critical field of ∼15 T. These findings suggest superconductivity may be induced by proper doping in narrow-gap semiconductors.

RbEuFe4As4 exhibits both superconducting order in the FeAs layers and ferromagnetic order in the Eu layers, providing a good platform to study the interaction and microscopic coexistence of these two traditionally incompatible orders. Growing high-quality RbEuFe4As4 single crystals is essential to investigate these phenomena at a deeper level. Here we report the successful growth of the RbEuFe4As4 single crystals with millimeter-size dimensions using a RbAs flux. The high-quality crystals were characterized via resistivity, magnetization, and heat capacity measurements. Single crystal X-ray diffraction data refinements reveal almost regular FeAs4 tetrahedra (As1–Fe–As1 = 108.60(7)°, As2–Fe–As2 = 109.01(8)°, and As1–Fe–As2 = 109.81(2)°) in RbEuFe4As4, providing structural support for the highest superconducting transition temperature (Tc = 36.8 K) among all known AAeFe4As4 (A = K, Rb, Cs; Ae = Ca, Sr, Eu) compounds. Our flux method using RbAs can also be employed to grow other desired transition metal comp...

We performed the experimental studies on La1-xCexMnO3 to investigate transport properties and field-induced transport mechanisms in electronic doped perovskite films. La1-xCexMnO3 films exhibit significant metal-insulator transition, which can be modulated by the doping ratio of Ce. Resistance-temperature curves indicate that the magnetic domains and electron-electron scattering mainly contribute to the transport mechanism in the low temperature region, while the hopping conduction of small polaron becomes the dominating factor at the high temperatures. Laser irradiation is found to induce the shift of metal-insulator transition temperature towards the lower temperature region due to the coexistence of ferromagnetic (FM) metallic phase and paramagnetic (PM) insulating phase in La1-xCexMnO3 films. The higher laser intensity gives rise to more significant change in resistance. Furthermore, magnetoresistance effect can be affected by different doping ratios of Ce in La1-xCexMnO3 films because of the MIT transition.

C7H8Ag2N3O4S, triclinic, P 1 ‾ $‾{1}$ (no. 2), a = 7.3758(3) Å, b = 8.7361(4) Å, c = 9.2906(4) Å, α = 112.877(4)°, β = 90.054(4)°, γ = 102.568(4)°, V = 535.90(4) Å3, Z = 2, R gt (F) = 0.0235, wR ref (F 2) = 0.0600, T = 293(2) K.

We report the synthesis, crystal structure and physical properties of a new layered oxypnictide Ba 2 Ti 2 Cr 2 As 4 O, which is isostructural to the Ba 2 Ti 2 Fe 2 As 4 O superconductor. Electrical resistivity and magnetic susceptibility demonstrate that this new compound is of metallic conduction with an anomaly occurring at 350 K, which is probably due to an antiferromagnetic (AFM) transition in the [Cr 2 As 2 ] 2− layers. The absence of the charge- or spin-density wave (CDW/SDW) instability in the [Ti 2 As 2 O] 2− layers was ascribed to the mixed occupation of Cr in the Ti sublattice. No superconductivity is observed down to 2 K.

(A = K, Rb, Cs) are the unique Cr-based ambient-pressure superconductors discovered in 2015. The new superconducting family are structurally characterised by quasi one-dimensional (Q1D) [() double-walled subnanotubes. Peculiar properties have been revealed, which mostly point to unconventional superconductivity. In this contribution, we first describe how the superconductors were discovered. Then we overview recent progress on the crystal structure, electronic structures, theoretical models and physical properties in . Some new experimental results are included. Finally, we conclude by addressing the related open questions in this emerging subfield of superconductivity.

C12H18O8N4S2Ag2, monoclinic, P21/c (no. 14), a = 10.7841(10) Å, b = 8.0140(5) Å, c = 11.7220(11) Å, β = 117.278(11)°, V = 900.40(16) Å3, Z = 2, R gt(F) = 0.0279, wR ref(F 2) = 0.0627, T = 293(2) K.

C12H30Ag2N4O11S2, monoclinic, I2/a (no. 15), a = 12.2643(8) Å, b = 7.1481(4) Å, c = 26.2858(16) Å, β = 93.119(6)°, V = 2301.0(2) Å3, Z = 4, Rgt (F) = 0.0186, wR ref(F 2) = 0.0462, T = 298(2) K.

Single crystals of a honeycomb lattice antiferromagnet, ${\mathrm{Tb}}_{2}{\mathrm{Ir}}_{3}{\mathrm{Ga}}_{9}$, were synthesized, and the physical properties have been studied. From magnetometry, a long-range antiferromagnetic ordering at $\ensuremath{\approx}12.5$ K with highly anisotropic magnetic behavior was found. Neutron powder diffraction confirms that the Tb spins lie along the $\mathbf{a}$-axis, parallel to the shortest Tb-Tb contact. Two field-induced spin-flip transitions are observed when the field is applied parallel to this axis, separated by a plateau corresponding roughly to $M\ensuremath{\approx}{M}_{\mathrm{s}}/2$. Transport measurements show the resistivity to be metallic with a discontinuity at the onset of N\'eel order. Heat capacity shows a $\ensuremath{\lambda}$-like transition confirming the bulk nature of the magnetism. We propose a phenomenological spin Hamiltonian that describes the magnetization plateau as a result of strong Ising character arising from a quasidoublet ground state of the ${\mathrm{Tb}}^{3+}$ ion in a site of ${C}_{s}$ symmetry and expressing a significant bond-dependent anisotropy.

Thermal fluctuations always melt the vortex lattice in type-II superconductors at temperatures below the mean-field transition. The extent of the intermediate vortex-liquid state varies widely among different materials. Exploring the vortex-lattice melting in the magnetic iron arsenide RbEuFe${}_{4}$As${}_{4}$ via calorimetry and transport, the authors demonstrate here that the vortex liquid occupies a significant portion of the phase diagram and that the location of the melting line agrees with theoretical predictions without fitting parameters. Comparison with other materials reveals the universality of melting behavior.

We present a study of the upper critical field ${H}_{c2}$ of pristine and proton-irradiated ${\mathrm{RbEuFe}}_{4}{\mathrm{As}}_{4}$ crystals in pulsed magnetic fields of up to 65 T. The data for ${H}_{c2}$ reveal pronounced downwards curvature, particularly for the in-plane field orientation, and a superconducting anisotropy that decreases with decreasing temperature. These features are indicative of Pauli paramagnetic limiting. For the interpretation of these data, we use a model of a clean single-band superconductor with an open Fermi surface in the shape of a warped cylinder, which takes into account Zeeman spin splitting. Fits to the data reveal that the in-plane upper critical field is Pauli paramagnetic limited, while the out-of-plane upper critical field is orbitally limited and that the orbital and paramagnetic fields have opposite anisotropies. A consequence of this particular combination is the unusual inversion of the anisotropy ${H}_{c2}^{ab}l{H}_{c2}^{c}$ of the irradiated sample at temperatures below 10 K. The fits also yield an in-plane Maki parameter ${\ensuremath{\alpha}}_{M}^{110}\ensuremath{\approx}2.6$ exceeding the critical value for the formation of the Fulde-Ferrell-Larkin-Ovchinnikov state. Nevertheless, the current measurements did not reveal direct evidence for the occurrence of this state.

The charge and spin of the electrons in solids have been extensively exploited in electronic devices and in the development of spintronics. Another attribute of electrons—their orbital nature—is attracting growing interest for understanding exotic phenomena and in creating the next-generation of quantum devices such as orbital qubits. Here, we report on orbital-flop induced magnetoresistance anisotropy in CeSb. In the low temperature high magnetic-field driven ferromagnetic state, a series of additional minima appear in the angle-dependent magnetoresistance. These minima arise from the anisotropic magnetization originating from orbital-flops and from the enhanced electron scattering from magnetic multidomains formed around the first-order orbital-flop transition. The measured magnetization anisotropy can be accounted for with a phenomenological model involving orbital-flops and a spin-valve-like structure is used to demonstrate the viable utilization of orbital-flop phenomenon. Our results showcase a contribution of orbital behavior in the emergence of intriguing phenomena., The orbital degree of freedom can be as important as the charge and spin of the electron to the electronic phenomena. Here the authors show additional minimum in the angle-dependent magnetoresistance (MR) for the low temperature high magnetic field driven ferromagnetic state in CeSb which indicates the orbital flop induced MR anisotropy.

The pressure dependencies of the magnetic and superconducting transitions, as well as that of the superconducting upper critical field are reported for single crystalline EuRbFe$_4$As$_4$. Resistance measurements were performed under hydrostatic pressures up to 6.21 GPa and in magnetic fields up to 9 T. Zero-field-cool magnetization measurements were performed under hydrostatic pressures up to 1.24 GPa under 20 mT applied field. Superconducting transition temperature, $T_\text c$, up to 6.21 GPa and magnetic transition temperature, $T_\text M$, up to 1.24 GPa were obtained and a pressure-temperature phase diagram was constructed. Our results show that $T_\text c$ is monotonically suppressed upon increasing pressure. $T_\text M$ is linearly increased up to 1.24 GPa. For the studied pressure range, no signs of the crossing of $T_\text M$ and $T_\text c$ lines are observed. The normalized slope of the superconducting upper critical field is gradually suppressed with increasing pressure, which may be due to the continuous change of Fermi-velocity $v_F$ with pressure.

We report an unusual enhancement of the magnetic induction in single crystals of the magnetic superconductor ${\mathrm{RbEuFe}}_{4}{\mathrm{As}}_{4}$, highlighting the interplay between superconducting and magnetic subsystems in this material. Contrary to the conventional Meissner expulsion of magnetic flux below the superconducting transition temperature, we observe a substantial boost of the magnetic flux density upon approaching the magnetic transition temperature, ${T}_{m}$. Direct imaging of the flux evolution with a magneto-optical technique, shows that the magnetic subsystem serves as an internal magnetic flux pump, drawing Abrikosov vortices from the surface, while the superconducting subsystem controls their conveyance into the bulk of the magnetic superconductor via a peculiar self-organized critical state.

Lithium-ion batteries based on conversion/alloying reactions have high potential applications in various electric energy storage. SnO2-based anode materials for LIBs have been considered as promising choices. However, their development is hindered by inherent large-volume variations and sluggish kinetics during discharge and charge processes. The W-doped SnO2 nanoparticles are evenly embedded in the graphite nanosheets (W-SnO2-C) via a facile ball milling method. The W doping can improve its electronic conductivity and stabilize the structure during cycling. Meanwhile, the ultrathin graphite wrapping effectively buffers the large volumetric variation of the SnO2-based anodes as well as shorten the diffusion path of electron and lithium-ion. The W-SnO2-C exhibits a reversible capacity of 1148.8 mAh g−1 at 0.2 Ag−1 after 500 cycles, with a high initial coulombic efficiency (ICE) of 76.2%. Furthermore, it shows remarkable rate performance with the capacity of 312.3 mAh g−1 at 5.0 Ag−1 and long-term cycling stability with a capacity of 1229.5 mAh g−1 after 800 cycles at 1.0 Ag−1. The first-principles calculations reveal that the final free energy of W-SnO2 is −3413.94 eV, which is much lower than that of SnO2 (−1937.4 eV), indicating the structure of the composite for W doping is more stability than SnO2-based anodes.

We report detailed specific heat measurements on the recently discovered magnetic superconductor RbEuFe$_4$As$_4$. We investigated the superconducting transition at 37K and extract the phase boundary for in and out-of plane fields resulting in an anisotropy ratio of 1.8. An unusual cusp-like feature in the calorimetric data near 14.9K marks the onset of a magnetic phase. Studying the effect of small fields along the crystallographic $c$ axis, we resolve a shift in the cusp position moving to lower temperatures. For in-plane fields the cusp rapidly disappears and a broad shoulder that shifts to higher temperatures. We are able to reproduce our measured calorimetry data quantitatively by Monte-Carlo simulations of an anisotropic easy-plane 2D Heisenberg model. We can thus show that (i) the spins are preferably in plane, (ii) the cusp in specific heat is due to a Berezinskii-Kosterlitz-Thouless (BKT) transition, and (iii) the high-temperature hump in higher fields marks a crossover from a paramagnetically disordered to an ordered state. The extracted phase and crossover boundaries from experiment and simulations agree very well., 5 pages, 4figures, 7 pages supplementary material

An experiment is performed to reconstruct an unknown photonic quantum state with a limited amount of copies. A semi-quantum reinforcement learning approach is employed to adapt one qubit state, an "agent," to an unknown quantum state, an "environment," by successive single-shot measurements and feedback, in order to achieve maximum overlap. The experimental learning device herein, composed of a quantum photonics setup, can adjust the corresponding parameters to rotate the agent system based on the measurement outcomes "0" or "1" in the environment (i.e., reward/punishment signals). The results show that, when assisted by such a quantum machine learning technique, fidelities of the deterministic single-photon agent states can achieve over 88% under a proper reward/punishment ratio within 50 iterations. This protocol offers a tool for reconstructing an unknown quantum state when only limited copies are provided, and can also be extended to higher dimensions, multipartite, and mixed quantum state scenarios.

We investigate the anisotropic superconducting and magnetic properties of single-crystal RbEuFe$_4$As$_4$ using magnetotransport and magnetization measurements. We determine a magnetic ordering temperature of the Eu-moments of $T_m$ = 15 K and a superconducting transition temperature of $T_c$ = 36.8 K. The superconducting phase diagram is characterized by high upper critical field slopes of -70 kG/K and -42 kG/K for in-plane and out-of-plane fields, respectively, and a surprisingly low superconducting anisotropy of $\Gamma$ = 1.7. Ginzburg-Landau parameters of $\kappa_c \sim 67$ and $\kappa_{ab} \sim 108$ indicate extreme type-II behavior. These superconducting properties are in line with those commonly seen in optimally doped Fe-based superconductors. In contrast, Eu-magnetism is quasi-two dimensional as evidenced by highly anisotropic in-plane and out-of-plane exchange constants of 0.6 K and $, Comment: 9 pages, 9 figures

C10H24Ag2N2O10S2, triclinic, P1̄ (no. 2), a = 6.9547(9) Å, b = 8.4684(12) Å, c = 8.9563(15) Å, α = 117.888(15)°, β = 101.740(13)°, γ = 93.026(11)°, V = 449.75(13) Å3, Z = 1, R gt(F) = 0.0365, wR ref(F 2) = 0.0858, T = 293(2) K.

C19H15N3NiO10, monoclinic, P21/c (no. 14), a = 12.7175(10) Å, b = 10.6780(10) Å, c = 15.0802(16) Å, β = 96.786(9)°, V = 2033.5(3) Å3, Z = 4, R gt(F) = 0.0358, wR ref(F 2) = 0.0960, T = 293(2) K.

C12H21Ag2N5O8S2, triclinic, P1 (no. 1), a = 6.3703(5) Å, b = 6.4191(5) Å, c = 12.3215(7) Å, α = 87.841(5)°, β = 75.119(6)°, γ = 87.489(6)°, V = 486.30(6) Å3, Z = 1, Rgt (F) = 0.0444, wR ref(F 2) = 0.1289, T = 293(2) K.

C22H30Ag2N9O6S2, monoclinic, P21 /c (no. 14), a = 10.4629(10) Å, b = 10.9785(8) Å, c = 12.3483(15) Å, β = 109.766(12)°, V = 1334.8(2) Å3, Z = 2, Rgt (F) = 0.0662, wR ref(F 2) = 0.1356, T = 293(2) K.

C14H16Ag2N5O8S2, triclinic, P1̄ (no. 2), a = 7.1305(7) Å, b = 7.3558(6) Å, c = 9.8517(10) Å, α = 73.816(9)°, β = 82.648(8)°, γ = 88.080(7)°, V = 492.17(8) Å3, Z = 1, Rgt (F) = 0.0491, wR ref(F 2) = 0.1515, T = 293(2) K.

A transport model with double Gaussian density of state (DOS) for organic semiconductors is proposed, with one Gaussian DOS for free carriers and one for trapped carriers. The variations of the density of trapped carriers with the density of free carriers, the effective mobility and the ratio of diffusion coefficient to effective mobility with the density of trapped carriers are analyzed. It is shown that the ratio of diffusion coefficient to effective mobility is the Einstein type for free carriers, but the ratio for total carriers is the non-Einstein type, and is an increasing function of the density of trapped carriers at low density, and a decreasing function at high density. The importance of non-symmetric barriers at contacts is emphasized to quantitatively describe the current–voltage relationships of typical organic layers sandwiched between two metallic electrodes. It is shown that slopes of current–voltage curves at low bias are very sensitive to the values of right barriers. The slopes in all bias are sensitive to the values of left barriers, and increase as the left barrier decreases. When applying the modified model to three organic diodes, an excellent agreement is obtained between theoretical results and experimental data.