Influence of magnetism, strain and pressure on the band topology of EuCd$_2$As$_2$

TL;DR

This paper investigates how EuCd$_2$As$_2$'s magnetic properties, strain, and pressure influence its topological electronic phases, revealing a complex phase diagram with multiple non-trivial topological states.

Contribution

It combines group theory and ab initio calculations to map out the diverse topological phases achievable in EuCd$_2$As$_2$ under various conditions.

Findings

Identification of multiple non-trivial topological phases including axion and crystalline insulators

Discovery of a rich phase diagram influenced by magnetism, strain, and pressure

Potential realization of various topological states beyond Weyl semimetals

Abstract

Motivated by the wealth of proposals and realizations of nontrivial topological phases in EuCd$_2$As$_2$, such as a Weyl semimetallic state and the recently discussed semimetallic versus semiconductor behavior in this system, we analyze in this work the role of the delicate interplay of Eu magnetism, strain and pressure on the realization of such phases. For that we invoke a combination of a group theoretical analysis with ab initio density functional theory calculations and uncover a rich phase diagram with various non-trivial topological phases beyond a Weyl semimetallic state, such as axion and topological crystalline insulating phases, and discuss their realization.