We report the detailed crystal structures and physical properties of Ru_(1-x)Mo_(x)alloys in the solid solution range of x=0.1-0.9.Structure characterizations indicate that the crystal structure changes from the hcp-M...We report the detailed crystal structures and physical properties of Ru_(1-x)Mo_(x)alloys in the solid solution range of x=0.1-0.9.Structure characterizations indicate that the crystal structure changes from the hcp-Mg-type,toβ-CrFe-type,and then bcc-W-type.The measurements of physical properties show that the Ru_(1-x)Mo_(x)samples with x≥0.2are superconductors and the superconducting transition temperature T_c as a function of Mo content exhibits a dome-like behavior.展开更多
Heat in solids can be transported by various quasiparticles, making low-temperature heat transport a powerfultool for probing charge-neutral excitations in quantum materials. In recent years, ultralow-temperature heat...Heat in solids can be transported by various quasiparticles, making low-temperature heat transport a powerfultool for probing charge-neutral excitations in quantum materials. In recent years, ultralow-temperature heattransport has been instrumental in detecting exotic excitations in quantum spin liquids (QSLs). A non-zeroresidual thermal conductivity, κ0/T, serves as compelling evidence for the presence of itinerant spinons andthe gapless nature of a disordered state. Additionally, the thermal Hall effect (THE) in QSLs can arise fromcontributions by spinons or Majorana fermions. In this review, we summarize key thermal conductivity findingsfrom various QSL candidates, focusing on the role of spinons in both heat transport and phonon scattering.We also examine different experimental observations and the underlying mechanisms of THE in QSL candidateswith three-dimensional pyrochlore structures, as well as two-dimensional honeycomb and triangular lattices. Thisreview offers valuable insights and guidance for understanding ultralow-temperature heat transport in QSLs.展开更多
We report the magnetotransport and thermal properties of RuAs_(2) single crystal.RuAs_(2) exhibits semiconductor behavior and localization effect.The crossover from normal state to diffusive transport in the weak loca...We report the magnetotransport and thermal properties of RuAs_(2) single crystal.RuAs_(2) exhibits semiconductor behavior and localization effect.The crossover from normal state to diffusive transport in the weak localization(WL)state and then to variable range hopping(VRH)transport in the strong localization state has been observed.The transitions can be reflected in the measurement of resistivity and Seebeck coefficient.Negative magnetoresistance(NMR)emerges with the appearance of localization effect and is gradually suppressed in high magnetic field.The temperature dependent phase coherence length extracted from the fittings of NMR also indicates the transition from WL to VRH.The measurement of Hall effect reveals an anomaly of temperature dependent carrier concentration caused by localization effect.Our findings show that RuAs_(2) is a suitable platform to study the localized state.展开更多
SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as ...SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as crystal symmetry,elements doping,oxygen vacancies,magnetic field,and temperature.Here,we find that the engineered carrier density plays a critical role on the magnetoelectric transport properties of the topological semimetal SrIrO_(3).The decrease of carrier density subdues the weak localization and the associated negative magnetoresistance,while enhancing the SOC-induced weak anti-localization.Notably,the sample with the lowest carrier density exhibits high-field positive magnetoresistance,suggesting the presence of a Dirac cone.In addition,the anisotropic magnetoresistance indicates the anisotropy of the electronic structure near the Fermi level.The engineering of carrier density provides a general strategy to control the Fermi surface and electronic structure in topological materials.展开更多
Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque(SOT)-induced magnetization switching, the critical currents required to switc...Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque(SOT)-induced magnetization switching, the critical currents required to switch between the two magnetization states(upward and downward magnetization) are asymmetric. In addition, in the nanowire structure, tilted anisotropy induces formation of tilted domain walls(DWs). The tilted DWs exhibit a ratchet behavior during motion. The ratchet effect during switching and DW motions can be tuned by changing the current direction with respect to the tilting direction of anisotropy. The ratchet motion of the DWs can be used to mimic the leaky-integrate-fire function of a biological neuron, especially the asymmetric property of the “potential” and “reset” processes. Our results provide a full understanding of the influence of tilted perpendicular anisotropy on SOT-induced magnetization switching and DW motion, and are beneficial for designs of further SOT-based devices.展开更多
基金Project supported by Beijing Natural Science Foundation (Grant No.Z200005)the National Key R&D Program of China (Grant Nos.2018YFE0202600 and 2022YFA1403800)+1 种基金the National Natural Science Foundation of China (Grant No.12274459)Beijing National Laboratory for Condensed Matter Physics,and Collaborative Research Project of Laboratory for Materials and Structures,Institute of Innovative Research,Tokyo Institute of Technology。
文摘We report the detailed crystal structures and physical properties of Ru_(1-x)Mo_(x)alloys in the solid solution range of x=0.1-0.9.Structure characterizations indicate that the crystal structure changes from the hcp-Mg-type,toβ-CrFe-type,and then bcc-W-type.The measurements of physical properties show that the Ru_(1-x)Mo_(x)samples with x≥0.2are superconductors and the superconducting transition temperature T_c as a function of Mo content exhibits a dome-like behavior.
文摘Heat in solids can be transported by various quasiparticles, making low-temperature heat transport a powerfultool for probing charge-neutral excitations in quantum materials. In recent years, ultralow-temperature heattransport has been instrumental in detecting exotic excitations in quantum spin liquids (QSLs). A non-zeroresidual thermal conductivity, κ0/T, serves as compelling evidence for the presence of itinerant spinons andthe gapless nature of a disordered state. Additionally, the thermal Hall effect (THE) in QSLs can arise fromcontributions by spinons or Majorana fermions. In this review, we summarize key thermal conductivity findingsfrom various QSL candidates, focusing on the role of spinons in both heat transport and phonon scattering.We also examine different experimental observations and the underlying mechanisms of THE in QSL candidateswith three-dimensional pyrochlore structures, as well as two-dimensional honeycomb and triangular lattices. Thisreview offers valuable insights and guidance for understanding ultralow-temperature heat transport in QSLs.
基金Project supported by the National Key Research and Development Program of China (Grant Nos.2023YFA1406500 and 2019YFA0308602)the National Natural Science Foundation of China (Grant Nos.12104011,12274388,12074425,52102333,12104010,12204004,and 11874422)the Natural Science Foundation of Anhui Province (Grant Nos.2108085QA22 and 2108085MA16)。
文摘We report the magnetotransport and thermal properties of RuAs_(2) single crystal.RuAs_(2) exhibits semiconductor behavior and localization effect.The crossover from normal state to diffusive transport in the weak localization(WL)state and then to variable range hopping(VRH)transport in the strong localization state has been observed.The transitions can be reflected in the measurement of resistivity and Seebeck coefficient.Negative magnetoresistance(NMR)emerges with the appearance of localization effect and is gradually suppressed in high magnetic field.The temperature dependent phase coherence length extracted from the fittings of NMR also indicates the transition from WL to VRH.The measurement of Hall effect reveals an anomaly of temperature dependent carrier concentration caused by localization effect.Our findings show that RuAs_(2) is a suitable platform to study the localized state.
基金supported by the National Natural Science Foundation of China(Grant Nos.T2350005 and 5227123)the National Science Fund for Distinguished Young Scholars(Grant No.52225205)+1 种基金the National Key Research and Development Program of China(Grant Nos.2021YFA0718700 and 2023YFA1406500)the Fundamental Research Funds for the Central Universities。
文摘SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as crystal symmetry,elements doping,oxygen vacancies,magnetic field,and temperature.Here,we find that the engineered carrier density plays a critical role on the magnetoelectric transport properties of the topological semimetal SrIrO_(3).The decrease of carrier density subdues the weak localization and the associated negative magnetoresistance,while enhancing the SOC-induced weak anti-localization.Notably,the sample with the lowest carrier density exhibits high-field positive magnetoresistance,suggesting the presence of a Dirac cone.In addition,the anisotropic magnetoresistance indicates the anisotropy of the electronic structure near the Fermi level.The engineering of carrier density provides a general strategy to control the Fermi surface and electronic structure in topological materials.
基金supported by the National Natural Science Foundation of China (Grant No.12274108)the Natural Science Foundation of Zhejiang Province (Grant Nos.LY23A040008 and LY23A040008)the Basic Scientific Research Project of Wenzhou (Grant No.G20220025)。
文摘Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque(SOT)-induced magnetization switching, the critical currents required to switch between the two magnetization states(upward and downward magnetization) are asymmetric. In addition, in the nanowire structure, tilted anisotropy induces formation of tilted domain walls(DWs). The tilted DWs exhibit a ratchet behavior during motion. The ratchet effect during switching and DW motions can be tuned by changing the current direction with respect to the tilting direction of anisotropy. The ratchet motion of the DWs can be used to mimic the leaky-integrate-fire function of a biological neuron, especially the asymmetric property of the “potential” and “reset” processes. Our results provide a full understanding of the influence of tilted perpendicular anisotropy on SOT-induced magnetization switching and DW motion, and are beneficial for designs of further SOT-based devices.
