Axion insulator, Weyl points, quantum anomalous Hall effect and magnetic topological phase transition in Eu3In2As4

TL;DR

This paper predicts that Eu3In2As4 can host various magnetic topological phases, including axion insulators, Weyl semimetals, and quantum anomalous Hall effect, tunable via strain and magnetic field, based on first-principles calculations.

Contribution

It demonstrates the potential of Eu3In2As4 to realize multiple magnetic topological phases, including axion insulators and Weyl points, through strain and magnetic field tuning.

Findings

Eu3In2As4 can be tuned to an axion insulator with tensile strain.

External magnetic field induces Weyl points or nodal ring in Eu3In2As4.

Quantum anomalous Hall effect can be achieved in Eu3In2As4 multilayer films.

Abstract

The magnetic topological phases attract much interest, such as the axion insulator, higher-order topology, Weyl semimetals, and the quantum anomalous Hall effect (QAHE). Here, we predict that the axion insulator phase, magnetic Weyl points, and QAHE can be achieved in Eu3In2As4. Recently, the single-crystal Eu3In2As4 has been successfully synthesized, which exhibits an antiferromagnetic (AFM) ground state. Our first-principles calculations show that it lies on the phase boundary between multiple magnetic topological phases, and the magnetic anisotropy is weak, with an energy difference less than 1 meV. In the AFM state, it can be tuned to an axion insulator by tensile strain. The quantized axion angle $\theta = \pi$ and the magnetic higher-order topology are characterized by the parity index $Z_4 = 2$. By applying an external magnetic field, the induced ferromagnetic (FM) state becomes an ideal magnetic topological semimetal with a single pair of Weyl points or a nodal ring. The QAHE can be achieved in FM multilayer films of Eu3In2As4 on a magnetic insulating substrate.