# Intrinsic ferromagnetism and quantum anomalous Hall effect in CoBr2 monolayer

## TL;DR

This study predicts that CoBr2 monolayer exhibits intrinsic ferromagnetism and quantum anomalous Hall effect, making it a promising material for future spintronic applications due to its topological and magnetic properties.

## Contribution

First comprehensive theoretical prediction of intrinsic ferromagnetism and quantum anomalous Hall effect in CoBr2 monolayer using DFT and TB modeling.

## Key findings

- CoBr2 monolayer is dynamically stable and exfoliable.
- It exhibits intrinsic two-dimensional ferromagnetism.
- It becomes a topologically nontrivial insulator with Chern number C=4.

## Abstract

The electronic, magnetic, and topological properties of CoBr2 monolayer are studied in the frame-work of the density-functional theory (DFT) combined with tight-binding (TB) modeling in terms of Wannier basis. Our DFT investigation and Monte Carlo simulation show that there exists intrinsic two-dimensional ferromagnetism in the CoBr2 monolayer thanks to large out-of-plane magnetocrystalline anisotropic energy. Our further study shows that the spin-orbits coupling makes it become a topologically nontrivial insulator with quantum anomalous Hall effect and topological Chern number C=4, and its edge states can be manipulated by changing the width of its nanoribbons and applying strains. The CoBr2 monolayer can be exfoliated from the layered CoBr2 bulk material because its exfoliation energy is between those of graphene and MoS2 monolayer and it is dynamically stable. These results make us believe that the CoBr2 monolayer can make a promising spintronic material for future high-performance devices.