Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crysta...Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crystal growth of 166-type kagome magnetic materials,including HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6),GdMn_(6)Sn_(6)and GdV_(6)Sn_(6),by using the flux method with Sn as the flux.Among them,HfMn_(6)Sn_(6)and ZrMn_(6)Sn_(6)single crystals were grown for the first time.X-ray diffraction measurements reveal that all four samples crystallize in HfFe6Ge6-type hexagonal structure with space group P6/mmm.All samples show metallic behavior from temperature dependence of resistivity measurements,and the dominant carrier is hole,except for GdV6Sn6 which is electron dominated.All samples have magnetic order with different transition temperatures,HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6)and GdV_(6)Sn_(6)are antiferromagnetic with TN of 541 K,466 K and 4 K respectively,while GdMn_(6)Sn_(6)is ferrimagnetic with the critical temperature of about 470 K.This study will enrich the research platform of magnetic kagome materials and help explore the novel quantum phenomena in these interesting materials.The dataset of specific crystal structure parameters for HfMn_(6)Sn_(6)are available in Science Data Bank,with the link.展开更多
The hysteresis of magnetoresistance observed in superconductors is of great interest due to its potential connectionwith unconventional superconductivity.In this study,we perform electrical transport measurements on k...The hysteresis of magnetoresistance observed in superconductors is of great interest due to its potential connectionwith unconventional superconductivity.In this study,we perform electrical transport measurements on kagome superconductorCsV_(3)Sb_(5)nanoflakes and uncover unusual hysteretic behavior of magnetoresistance in the superconducting state.This hysteresis can be induced by applying either a large DC or AC current at temperatures(T)well below the superconductingtransition temperature(T_(c)).As T approaches T_(c),similar weak hysteresis is also detected by applying a smallcurrent.Various scenarios are discussed,with particular focus on the effects of vortex pinning and the presence of timereversal-symmtery-breaking superconducting domains.Our findings support the latter,hinting at chiral superconductivityin kagome superconductors.展开更多
V-based kagome superconductors AV_(3)Sb_(5)(A=K,Rb,and Cs)host a charge density wave(CDW)and a topological nontrivial band structure,thereby providing a great platform to study the interplay of superconductivity(SC),C...V-based kagome superconductors AV_(3)Sb_(5)(A=K,Rb,and Cs)host a charge density wave(CDW)and a topological nontrivial band structure,thereby providing a great platform to study the interplay of superconductivity(SC),CDW,frustration,and topology.Here,we report ultralow-temperature thermal conductivity measurements of CsV_(3)Sb_(5 ) and Ta-doped Cs((V_(0.86)Ta_(0.14)))_(3)Sb_(5) and scanning tunneling microscopy(STM)measurements of CsV_(3)Sb_(5 ).The finite residual linear term of thermal conductivity at zero magnetic field suggests the existence of a residual density of states(DOS)in the superconducting state of CsV_(3)Sb_(5 ).This is supported by the observation of non-zero conductance at zero bias in STM spectrum at an electronic temperature of 90 mK.However,in Cs(V_(0.86)Ta_(0.14))_(3)Sb_(5),which does not have CDW order,there is no evidence for the residual DOS.These results show the importance of CDW order for the residual DOS,and that a nodal s-wave gap or residual Fermi arc may be the origin of the residual DOS in such an unusual multiband kagome superconductor,CsV_(3)Sb_(5 ).展开更多
基金the Beijing Natural Science Founda-tion(Grant No.Z210006)the National Key Research and De-velopment Program of China(Grant Nos.2022YFA1403400 and 2020YFA0308800)the Beijing National Labora-tory for Condensed Matter Physics(Grant No.2023BNL-CMPKF007).
文摘Kagome magnets were predicted to be a good platform to investigate correlated topology band structure,Chern quantum phase,and geometrical frustration due to their unique lattice geometry.Here we reported single crystal growth of 166-type kagome magnetic materials,including HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6),GdMn_(6)Sn_(6)and GdV_(6)Sn_(6),by using the flux method with Sn as the flux.Among them,HfMn_(6)Sn_(6)and ZrMn_(6)Sn_(6)single crystals were grown for the first time.X-ray diffraction measurements reveal that all four samples crystallize in HfFe6Ge6-type hexagonal structure with space group P6/mmm.All samples show metallic behavior from temperature dependence of resistivity measurements,and the dominant carrier is hole,except for GdV6Sn6 which is electron dominated.All samples have magnetic order with different transition temperatures,HfMn_(6)Sn_(6),ZrMn_(6)Sn_(6)and GdV_(6)Sn_(6)are antiferromagnetic with TN of 541 K,466 K and 4 K respectively,while GdMn_(6)Sn_(6)is ferrimagnetic with the critical temperature of about 470 K.This study will enrich the research platform of magnetic kagome materials and help explore the novel quantum phenomena in these interesting materials.The dataset of specific crystal structure parameters for HfMn_(6)Sn_(6)are available in Science Data Bank,with the link.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Grant No.2024SDXHDX0007)the National Natural Science Foundation of China(Grant No.12474131)+4 种基金the China Postdoctoral Science Foundation(Grant Nos.2022M722845 and 2023T160586)the Zhejiang Provincial Natural Science Foundation of China for Distinguished Young Scholars(Grant No.LR23A040001)the Research Center for Industries of the Future(RCIF)at Westlake University(Grant No.WU2023C009)the National Key R&D Program of China(Grant Nos.2020YFA0308800 and 2022YFA1403400)the Beijing Natural Science Foundation(Grant No.Z210006).The authors thank the support provided by Dr.Chao Zhang from Instrumentation and Service Center for Physical Sciences at Westlake University.
文摘The hysteresis of magnetoresistance observed in superconductors is of great interest due to its potential connectionwith unconventional superconductivity.In this study,we perform electrical transport measurements on kagome superconductorCsV_(3)Sb_(5)nanoflakes and uncover unusual hysteretic behavior of magnetoresistance in the superconducting state.This hysteresis can be induced by applying either a large DC or AC current at temperatures(T)well below the superconductingtransition temperature(T_(c)).As T approaches T_(c),similar weak hysteresis is also detected by applying a smallcurrent.Various scenarios are discussed,with particular focus on the effects of vortex pinning and the presence of timereversal-symmtery-breaking superconducting domains.Our findings support the latter,hinting at chiral superconductivityin kagome superconductors.
文摘V-based kagome superconductors AV_(3)Sb_(5)(A=K,Rb,and Cs)host a charge density wave(CDW)and a topological nontrivial band structure,thereby providing a great platform to study the interplay of superconductivity(SC),CDW,frustration,and topology.Here,we report ultralow-temperature thermal conductivity measurements of CsV_(3)Sb_(5 ) and Ta-doped Cs((V_(0.86)Ta_(0.14)))_(3)Sb_(5) and scanning tunneling microscopy(STM)measurements of CsV_(3)Sb_(5 ).The finite residual linear term of thermal conductivity at zero magnetic field suggests the existence of a residual density of states(DOS)in the superconducting state of CsV_(3)Sb_(5 ).This is supported by the observation of non-zero conductance at zero bias in STM spectrum at an electronic temperature of 90 mK.However,in Cs(V_(0.86)Ta_(0.14))_(3)Sb_(5),which does not have CDW order,there is no evidence for the residual DOS.These results show the importance of CDW order for the residual DOS,and that a nodal s-wave gap or residual Fermi arc may be the origin of the residual DOS in such an unusual multiband kagome superconductor,CsV_(3)Sb_(5 ).
