Magnetic Weyl semimetals(WSMs)with broken time-reversal symmetry(TRS)hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics.Howeve...Magnetic Weyl semimetals(WSMs)with broken time-reversal symmetry(TRS)hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics.However,the experimental verification of magnetic WSMs is very challenging.Very recently,the kagome magnet Co3Sn2S2 was confirmed to be a magnetic WSM by both angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy and consequently has become the focus of great attention.This paper reports a point-contact Andreev-reflection spectroscopy(PCARS)investigation on the(001)surface and the side surface of the Co3Sn2S2 single crystals,respectively.The measurements from the sample’s(001)and side surfaces provide experimental evidence for transport spin polarization in the Co3Sn2S2 magnetic WSM.Furthermore,the superconducting proximity effect in the Co3Sn2S2 single crystal is successfully detected.The point-contact spectra(PCS)along the in-plane direction cannot be well fitted by theoretical models based on s-wave pairing,indicating that possible triplet p-wave superconductivity may be triggered at the interface,which paves the way for the future exploration of the topological superconductivity and Majorana states in broken TRS WSMs.展开更多
Introducing magnetism into topological insulators breaks timereversal symmetry,and the magnetic exchange interaction can open a gap in the otherwise gapless topological surface states.This allows various novel topolog...Introducing magnetism into topological insulators breaks timereversal symmetry,and the magnetic exchange interaction can open a gap in the otherwise gapless topological surface states.This allows various novel topological quantum states to be generated,including the quantum anomalous Hall effect(QAHE)and axion insulator states.Magnetic doping and magnetic proximity are viewed as being useful means of exploring the interaction between topology and magnetism.However,the inhomogeneity of magnetic doping leads to complicated magnetic ordering and small exchange gaps,and consequently the observed QAHE appears only at ultralow temperatures.Therefore,intrinsic magnetic topological insulators are highly desired for increasing the QAHE working temperature and for investigating topological quantum phenomena further.The realization and characterization of such systems are essential for both fundamental physics and potential technical revolutions.This review summarizes recent research progress in intrinsic magnetic topological insulators,focusing mainly on the antiferromagnetic topological insulator MnBi2Te4 and its family of materials.展开更多
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0305600,and 2017YFA0303302)the National Natural Science Foundation of China(Grant Nos.11888101,11774008,11774007,U1832214,and 11704279)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)the Beijing Natural Science Foundation(Grant Nos.Z180010,and 1202005)。
文摘Magnetic Weyl semimetals(WSMs)with broken time-reversal symmetry(TRS)hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics.However,the experimental verification of magnetic WSMs is very challenging.Very recently,the kagome magnet Co3Sn2S2 was confirmed to be a magnetic WSM by both angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy and consequently has become the focus of great attention.This paper reports a point-contact Andreev-reflection spectroscopy(PCARS)investigation on the(001)surface and the side surface of the Co3Sn2S2 single crystals,respectively.The measurements from the sample’s(001)and side surfaces provide experimental evidence for transport spin polarization in the Co3Sn2S2 magnetic WSM.Furthermore,the superconducting proximity effect in the Co3Sn2S2 single crystal is successfully detected.The point-contact spectra(PCS)along the in-plane direction cannot be well fitted by theoretical models based on s-wave pairing,indicating that possible triplet p-wave superconductivity may be triggered at the interface,which paves the way for the future exploration of the topological superconductivity and Majorana states in broken TRS WSMs.
基金This work was financially supported by the Beijing Natural Science Foundation(grant no.Z180010)the National Key R&D Program of China(2018YFA0305600,2017YFA0303302)+2 种基金the National Natural Science Foundation of China(grant nos.11888101 and 11774008)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB28000000)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics,Tsinghua University(grant no.KF202001).
文摘Introducing magnetism into topological insulators breaks timereversal symmetry,and the magnetic exchange interaction can open a gap in the otherwise gapless topological surface states.This allows various novel topological quantum states to be generated,including the quantum anomalous Hall effect(QAHE)and axion insulator states.Magnetic doping and magnetic proximity are viewed as being useful means of exploring the interaction between topology and magnetism.However,the inhomogeneity of magnetic doping leads to complicated magnetic ordering and small exchange gaps,and consequently the observed QAHE appears only at ultralow temperatures.Therefore,intrinsic magnetic topological insulators are highly desired for increasing the QAHE working temperature and for investigating topological quantum phenomena further.The realization and characterization of such systems are essential for both fundamental physics and potential technical revolutions.This review summarizes recent research progress in intrinsic magnetic topological insulators,focusing mainly on the antiferromagnetic topological insulator MnBi2Te4 and its family of materials.
