Chiral Dirac Fermion in a Collinear Antiferromagnet  

作　　者：张奥 邓可 盛洁明 刘鹏飞 Shiv Kumar Kenya Shimada 江志诚 刘正太 沈大伟 李嘉裕 任俊 王乐 周良 Yoshihisa Ishikawa Takashi Ohhara Qiang Zhang Garry McIntyre Dehong Yu 刘恩克 吴留锁 陈朝宇 刘奇航 Ao Zhang;Ke Deng;Jieming Sheng;Pengfei Liu;Shiv Kumar;Kenya Shimada;Zhicheng Jiang;Zhengtai Liu;Dawei Shen;Jiayu Li;Jun Ren;Le Wang;Liang Zhou;Yoshihisa Ishikawa;Takashi Ohhara;Qiang Zhang;Garry McIntyre;Dehong Yu;Enke Liu;Liusuo Wu;Chaoyu Chen;Qihang Liu(Shenzhen Institute for Quantum Science and Technology and Department of Physics,Southern University of Science and Technology,Shenzhen 518055,China;Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen 518055,China;Hiroshima Synchrotron Radiation Centre,Hiroshima University,Higashi-Hiroshima,Hiroshima 739-0046,Japan;State Key Laboratory of Functional Materials for Informatics and Center for Excellence in Superconducting Electronics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;Neutron Science and Technology Center,Comprehensive Research Organization for Science and Society,Tokai,Ibaraki 319-1106,Japan;Neutron Science Section,J-PARC Center,Japan Atomic Energy Agency,Ibaraki 319-1195,Japan;Neutron Science Division,Oak Ridge National Laboratory,Oak Ridge,Tennessee 37831,USA;Australian Nuclear Science and Technology Organisation,Locked bag 2001,Kirrawee DC,New South Wales 2232,Australia;State Key Laboratory for Magnetism,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]Shenzhen Institute for Quantum Science and Technology and Department of Physics,Southern University of Science and Technology,Shenzhen 518055,China [2]Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen 518055,China [3]Hiroshima Synchrotron Radiation Centre,Hiroshima University,Higashi-Hiroshima,Hiroshima 739-0046,Japan [4]State Key Laboratory of Functional Materials for Informatics and Center for Excellence in Superconducting Electronics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China [5]Neutron Science and Technology Center,Comprehensive Research Organization for Science and Society,Tokai,Ibaraki 319-1106,Japan [6]Neutron Science Section,J-PARC Center,Japan Atomic Energy Agency,Ibaraki 319-1195,Japan [7]Neutron Science Division,Oak Ridge National Laboratory,Oak Ridge,Tennessee 37831,USA [8]Australian Nuclear Science and Technology Organisation,Locked bag 2001,Kirrawee DC,New South Wales 2232,Australia [9]State Key Laboratory for Magnetism,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Chinese Physics Letters》2023年第12期84-91,共8页中国物理快报（英文版）

基　　金：supported by the National Key R&D Program of China (Grant Nos. 2020YFA0308900 and 2022YFA1403700);the National Natural Science Foundation of China (Grant Nos. 12074163, 12134020, 11974157, 12104255, 12004159, and 12374146);Guangdong Provincial Key Laboratory for Computational Science and Material Design (Grant No. 2019B030301001);the Science, Technology and Innovation Commission of Shenzhen Municipality (Grant Nos. ZDSYS20190902092905285 and KQTD20190929173815000);Guangdong Basic and Applied Basic Research Foundation (Grant Nos. 2022B1515020046, 2021B1515130007, 2022A1515011915, 2019A1515110712, and 2022B1515130005);Shenzhen Science and Technology Program (Grant Nos. RCJC20221008092722009 and RCBS20210706092218039);the Guangdong Innovative and Entrepreneurial Research Team Program (Grant No. 2019ZT08C044);the beam time awarded by Australia’s Nuclear Science and Technology Organisation (ANSTO) (Grant No. P8130);the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex (J-PARC) was performed under a user program (Proposal No. 2019B0140);performed at the Hiroshima Synchrotron Radiation Center (HiSOR) of Japan (Grant Nos. 22BG023 and 22BG029);Shanghai Synchrotron Radiation Facility (SSRF) BL03U (Grant No. 2022-SSRF-PT-020848)。

摘　　要：In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, it is predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral“Dirac-like” fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Such an unconventional chiral fermion, protected by a hidden SU(2) symmetry in the hierarchy of an enhanced crystallographic group, namely spin space group, is not experimentally verified yet. Here, by angle-resolved photoemission spectroscopy measurements, we reveal the surface origin of the electron pocket at the Fermi surface in collinear antiferromagnet CoNb3S6. Combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions.Our work provides spectral evidence of the chiral Dirac-like fermion caused by particular spin symmetry in CoNb_(3)S_(6), paving an avenue for exploring new emergent phenomena in antiferromagnets with unconventional quasiparticle excitations.

关 键 词：FERMI DIRAC CHIRAL 

分 类 号：O469[理学—凝聚态物理]