φ-映射拓扑流理论在Weyl半金属拓扑分类中的应用  

Applications of φ-mapping theory in describing Weyl topological semimetals

作　　者：黄晓红 姜颖 HUANG Xiaohong;JIANG Ying(College of Sciences,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学理学院,上海200444

出　　处：《上海大学学报（自然科学版）》2024年第1期106-117,共12页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金资助项目(11275119)。

摘　　要：用φ-映射拓扑流理论对厄米及非厄米Weyl半金属进行拓扑分类.对一个给定的哈密顿,在动量空间建立一个由自旋组成的■场,再由这个■场给出拓扑荷密度分布.发现只有在■场模的零点,拓扑荷密度的值才不为零,而这些■场模的零点其实就是Weyl点或Weyl奇异点所在位置.通过对拓扑荷密度的积分,得到了可用于对系统进行拓扑分类的整数拓扑数.In this study,we examine the topological classification of Weyl semimetals of Hermitian and non-Hermitian systems using φ-mapping topological current theory.We establish the ■ fields in the momentum space by the given Hamiltonians of two-band systems to define the topological charge density.We find that the topological charge density is nonzero only at the zeroes of the norm of the ■ fields,and these zeroes are exactly where Weyl points or Weyl exceptional points are located.The quantized numbers obtained by integrating the topological charge density can be used as the topological numbers for topological classification.

关 键 词：φ-映射拓扑流理论 拓扑分类 Weyl半金属 非厄米系统 

分 类 号：O469[理学—凝聚态物理]