Evolution of Weyl nodes in Ni-doped thallium niobate pyrochlore Tl_(2-x)Ni_(x)Nb_(2)O_(7)  

作　　者：Yuefang Hu Changming Yue Danwen Yuan Jiacheng Gao Zhigao Huang Zhong Fang Chen Fang Hongming Weng Wei Zhang 

机构地区：[1]Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials,College of Physics and Energy,Fujian Normal University,Fuzhou 350117,China [2]Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering,Fuzhou 350117,China [3]Department of Physics,University of Fribourg,Fribourg 1700,Switzerland [4]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [5]University of Chinese Academy of Sciences,Beijing 100049,China [6]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2022年第9期104-111,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11974076,11925408,11921004,and 12188101);Key Project of Natural Science Foundation of Fujian Province(Grant No.2021J02012);Ministry of Science and Technology of China(Grant No.2018YFA0305700);Chinese Academy of Sciences(Grant No.XDB33000000);K.C.Wong Education Foundation(Grant No.GJTD-2018-01);Informatization Plan of Chinese Academy of Sciences(Grant No.CAS-WX2021SF-0102);supported by the Swiss National Science Foundation(Grant No.200021-196966)。

摘　　要：The magnetic Weyl semimetal(WSM)is important for fundamental physics and potential applications due to its spontaneous magnetism,robust band topology,and enhanced Berry curvature.It possesses many unique quantum effects,including a large intrinsic anomalous Hall effect,Fermi arcs,and chiral anomaly.In this work,using ab initio calculations,we propose that Nidoped pyrochlore Tl2Nb2O7is a magnetic WSM caused by the exchange field splitting on bands around its quadratic band crossing point.The exchange field tuned by Ni 3d on-site Coulomb interaction parameter U drives the evolution of Weyl nodes and the resulting topological phase transition.As Weyl nodes can exist at generic points in the Brillouin zone and are hard to identify exactly,their creation and annihilation,i.e.,the change in their number,chirality,and distribution,have been consistently confirmed with a combined theoretical approach,which employs parity criterion,symmetry indicator analysis,and the Wilson loop of the Wannier center.We find that Weyl nodes remain in a large range of U and are close to the Fermi level,which makes the experimental observation very possible.We think that this method and our proposal of magnetic WSM will be useful in finding more WSMs and add to the understanding of the topological phase transition.

关 键 词：magnetic Weyl semimetal PYROCHLORE topological phase transition Chern number anomalous Hall effect 

分 类 号：O469[理学—凝聚态物理]