Tunable Dirac semimetals with higher-order Fermi arcs in Kagome lattices Pd_(3)Pb_(2)X_(2)(X=S,Se)  

具有高阶费米弧的可调狄拉克半金属:Kagome晶格Pd_(3)Pb_(2)X_(2)

作　　者：Simin Nie Jia Chen Changming Yue Congcong Le Danwen Yuan Zhijun Wang Wei Zhang Hongming Weng 聂思敏;陈佳;岳长明;乐聪聪;袁丹文;王志俊;张薇;翁红明(Department of Materials Science and Engineering,Stanford University,Stanford CA 94305,USA;Zhejiang Lab,Hangzhou 311121,China;Department of Physics,University of Fribourg,Fribourg 1700,Switzerland;RIKEN Interdisciplinary Theoretical and Mathematical Sciences(iTHEMS),Wako,Saitama 351-0198,Japan;Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials,College of Physics and Energy,Fujian Normal University,Fuzhou 350117,China;Fujian Provincial Collaborative Innovation Center for Advanced High-field Superconducting Materials and Engineering,Fuzhou 350117,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physics,University of Chinese Academy of Sciences,Beijing 100049,China;Songshan Lake Materials Laboratory,Dongguan 523808,China)

机构地区：[1]Department of Materials Science and Engineering,Stanford University,Stanford CA 94305,USA [2]Zhejiang Lab,Hangzhou 311121,China [3]Department of Physics,University of Fribourg,Fribourg 1700,Switzerland [4]RIKEN Interdisciplinary Theoretical and Mathematical Sciences(iTHEMS),Wako,Saitama 351-0198,Japan [5]Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials,College of Physics and Energy,Fujian Normal University,Fuzhou 350117,China [6]Fujian Provincial Collaborative Innovation Center for Advanced High-field Superconducting Materials and Engineering,Fuzhou 350117,China [7]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [8]School of Physics,University of Chinese Academy of Sciences,Beijing 100049,China [9]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Science Bulletin》2022年第19期1958-1961,共4页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(11974076,11925408,11921004,and 12188101);the Key Project of Natural Science Foundation of Fujian Province(2021J02012);the Ministry of Science and Technology of China(2018YFA0305700);the Chinese Academy of Sciences(XDB33000000 and CAS-WX2021SF-0102);the K.C.Wong Education Foundation(GJTD-2018–01);the Key Research Project of Zhejiang Lab(2021PB0AC01);supported by the Swiss National Science Foundation(200021–196966)。

摘　　要：Over the decade,Dirac semimetals(DSMs)have been extensively studied[1].However,the hallmarks of DSMs are still not clear[2,3].Recently,a generalized bulk-boundary correspondence,namely higher-order bulk-hinge correspondence,for DSMs[4–7]has been proposed,i.e.,one-dimensional(1D)higher-order Fermi arcs(HOFAs)are direct and topological consequences of 3D bulk Dirac points.The 3D bulk Dirac points lead to the nontrivial filling anomalyη[8,9]of the 2D insulating momentum-space plane away from them,which ensures the presence of gapless mid-gap states on 1D hinges.近十年来,狄拉克半金属因其独特的物性而受到了广泛的关注和研究.然而它的特征仍然不清楚.体-边界对应关系在识别拓扑态方面取得了巨大成功,但是人们在理论上发现该对应关系并不适用于狄拉克半金属.本文通过第一性原理计算和低能有效模型分析提出kagome晶格材料Pd_(3)Pb_(2)X_(2)(X=S,Se)是独特的第一类狄拉克半金属.它们的表面没有费米弧,这不同于人们所熟知的狄拉克半金属Na_(3)Bi和Cd_(3)As_(2).该结果充分表明表面费米弧的存在不是狄拉克半金属的必要条件.由于体-铰链对应,非平庸的拓扑不变量保证在它们的特定铰链上存在高阶费米弧和分数电荷.这些铰链上的独特性质是三维狄拉克点的直接和拓扑结果.此外,Pd_(3)Pb_(2)X_(2)也可以通过外部应力驱动为第二类狄拉克半金属或弱拓扑绝缘体.本工作为这些独特的狄拉克半金属以及其相关拓扑相变的研究提供了可行的平台.

关 键 词：狄拉克 半金属 分数电荷 拓扑绝缘体 拓扑不变量 

分 类 号：TB34[一般工业技术—材料科学与工程]