Topological semimetals studied by ab initio calculations

TL;DR

This paper reviews recent ab initio computational methods and theoretical frameworks for identifying and studying topological semimetals, which have unique electronic structures characterized by band crossings not confined to high-symmetry points.

Contribution

It introduces new computational approaches and theoretical insights that improve the search and analysis of topological semimetals using ab initio calculations.

Findings

Reviewed ab initio methods for topological semimetals

Outlined theoretical frameworks for material search

Discussed numerical techniques for band structure analysis

Abstract

In topological semimetals such as Weyl, Dirac, and nodal-line semimetals, the band gap closes at points or along lines in k space which are not necessarily located at high-symmetry positions in the Brillouin zone. Therefore, it is not straightforward to find these topological semimetals by ab initio calculations because the band structure is usually calculated only along high-symmetry lines. In this paper, we review recent studies on topological semimetals by ab initio calculations. We explain theoretical frameworks which can be used for the search for topological semimetal materials, and some numerical methods used in the ab initio calculations.