The measurements of magnetization,longitudinal and Hall resistivities are carried out on the intrinsic antiferromagnetic(AFM) topological insulator ElSn2 As2.It is confirmed that our ElSn2 As2 crystal is a heavily hol...The measurements of magnetization,longitudinal and Hall resistivities are carried out on the intrinsic antiferromagnetic(AFM) topological insulator ElSn2 As2.It is confirmed that our ElSn2 As2 crystal is a heavily hole doping A-type AFM metal with the Neel temperature TN=24 K,with a metamagnetic transition from an AFM to a ferromagnetic(FIM) phase occurring at a certain critical magnetic Held for the different Held orientations.Meanwhile,we also find that the carrier concentration does not change with the evolution of magnetic order,indicating that the weak interaction between the localized magnetic moments from Eu2+4f7 orbits and the electronic states near the Fermi level.Although the quantum anomalous Hall effect(AHE) is not observed in our crystals,it is found that a relatively large negative magnetoresistance (-13%) emerges in the AFM phase,and exhibits an exponential dependence upon magnetic Held,whose microscopic origin is waiting to be clarified in future research.展开更多
Compounds with the A15 structure have attracted extensive attention due to their superconductivity and nontrivial topological band structures.We have successfully grown Nb_(3)Sb single crystals with the A15 structure ...Compounds with the A15 structure have attracted extensive attention due to their superconductivity and nontrivial topological band structures.We have successfully grown Nb_(3)Sb single crystals with the A15 structure and systematically measured the longitudinal resistivity,Hall resistivity and quantum oscillations in magnetization.Similar to other topological trivial/nontrivial semimetals,Nb_(3)Sb exhibits large magnetoresistance(MR)at low temperatures(717%,2 K and 9 T),unsaturating quadratic field dependence of MR and up-turn behavior in ρ_(xx)(T)curves under magnetic field,which is considered to result from a perfect hole-electron compensation,as evidenced by the Hall resistivity measurements.The nonzero Berry phase obtained from the de-Hass van Alphen(dHvA)oscillations demonstrates that Nb_(3)Sb is topologically nontrivial.These results indicate that Nb_(3)Sb superconductor is also a semimetal with large MR and nontrivial Berry phase.This indicates that Nb_(3)Sb may be another platform to search for the Majorana zero-energy mode.展开更多
基金Supported by the National Key Research and Development Program of China under Grant No.2016YFA0300402the National Basic Research Program of China under Grant No.2015CB921004+2 种基金the National Natural Science Foundation of China under Grant Nos.11974095 and 11374261the Zhejiang Natural Science Foundation(No.LY16A040012)the Fundamental Research Funds for the Central Universities.
文摘The measurements of magnetization,longitudinal and Hall resistivities are carried out on the intrinsic antiferromagnetic(AFM) topological insulator ElSn2 As2.It is confirmed that our ElSn2 As2 crystal is a heavily hole doping A-type AFM metal with the Neel temperature TN=24 K,with a metamagnetic transition from an AFM to a ferromagnetic(FIM) phase occurring at a certain critical magnetic Held for the different Held orientations.Meanwhile,we also find that the carrier concentration does not change with the evolution of magnetic order,indicating that the weak interaction between the localized magnetic moments from Eu2+4f7 orbits and the electronic states near the Fermi level.Although the quantum anomalous Hall effect(AHE) is not observed in our crystals,it is found that a relatively large negative magnetoresistance (-13%) emerges in the AFM phase,and exhibits an exponential dependence upon magnetic Held,whose microscopic origin is waiting to be clarified in future research.
基金the National Key R&D Program of China(Grant No.2016YFA0300402)the National Natural Science Foundation of China(Grant Nos.12074335,and 11974095)the Fundamental Research Funds for the Central Universities。
文摘Compounds with the A15 structure have attracted extensive attention due to their superconductivity and nontrivial topological band structures.We have successfully grown Nb_(3)Sb single crystals with the A15 structure and systematically measured the longitudinal resistivity,Hall resistivity and quantum oscillations in magnetization.Similar to other topological trivial/nontrivial semimetals,Nb_(3)Sb exhibits large magnetoresistance(MR)at low temperatures(717%,2 K and 9 T),unsaturating quadratic field dependence of MR and up-turn behavior in ρ_(xx)(T)curves under magnetic field,which is considered to result from a perfect hole-electron compensation,as evidenced by the Hall resistivity measurements.The nonzero Berry phase obtained from the de-Hass van Alphen(dHvA)oscillations demonstrates that Nb_(3)Sb is topologically nontrivial.These results indicate that Nb_(3)Sb superconductor is also a semimetal with large MR and nontrivial Berry phase.This indicates that Nb_(3)Sb may be another platform to search for the Majorana zero-energy mode.
