Correlation-driven topological transition in Janus VSiGeP2As2

TL;DR

This study investigates the magnetic and topological properties of Janus VSiGeP2As2 monolayers, revealing a correlation-driven topological transition influenced by strain and Coulomb interactions, with implications for 2D magnetic topological materials.

Contribution

First-principles analysis of magnetic anisotropy and topological transitions in Janus VSiGeP2As2, highlighting strain effects and Coulomb interaction influence on topology.

Findings

All three monolayers exhibit robust ferromagnetism.

Janus VSiGeP2As2 undergoes a correlation-driven topological transition.

Magnetization orientation varies among the monolayers.

Abstract

The appearance of intrinsic ferromagnetism in 2D materials opens the possibility of investigating the interplay between magnetism and topology. The magnetic anisotropy energy (MAE) describing the easy axis for magnetization in a particular direction is an important yardstick for nanoscale applications. Here, the first-principles approach is used to investigate the electronic band structures, the strain dependence of MAE in pristine VSi2Z4 (Z=P, As) and its Janus phase VSiGeP2As2 and the evolution of the topology as a function of the Coulomb interaction. In the Janus phase the compound presents a breaking of the mirror symmetry, which is equivalent to having an electric field, and the system can be piezoelectric. It is revealed that all three monolayers exhibit ferromagnetic ground state ordering, which is robust even under biaxial strains. A large value of coupling J is obtained, and this, together with the magnetocrystalline anisotropy, will produce a large critical temperature. We found an out-of-plane (in-plane) magnetization for VSi2P4 (VSi2As4), while in-plane magnetization for VSiGeP2As2. Furthermore, we observed a correlation-driven topological transition in the Janus VSiGeP2As2. Our analysis of these emerging pristine and Janus-phased magnetic semiconductors opens prospects for studying the interplay between magnetism and topology in two-dimensional materials.