Quantum anomalous Hall effect in monolayer transition-metal trihalides

TL;DR

This study uses first-principles calculations to identify monolayer transition-metal trihalides that can host the quantum anomalous Hall effect, revealing topological phases and edge states.

Contribution

It systematically explores the electronic and magnetic properties of MX3 monolayers, identifying candidates with nontrivial topological phases due to spin-orbit coupling.

Findings

MnF3 and PdF3 exhibit spin-polarized Dirac cones with sizable gaps.

Nanoribbon calculations show gap-crossing chiral edge states.

Systematic trends across MX3 family elucidate conditions for topological phases.

Abstract

We present systematic first-principles results for the electronic and magnetic properties of two-dimensional transition-metal trihalide monolayers MX3 (M = V, Cr, Mn, Fe, Ni, Pd; X = F, Cl, Br, I), focusing on their potential to host the quantum anomalous Hall effect. In particular, MnF3 and PdF3 exhibit a spin-polarized Dirac cone at the K point, spin-orbit coupling opens a sizable gap with a nonzero Chern number. Nanoribbon slab calculations reveal gap-crossing chiral edge states, establishing the nontrivial topological character. Beyond these case studies, our systematic screening clarifies general trends across the MX3 family and provides insight into how electronic configuration and spin-orbit coupling cooperate to produce magnetic and topological phases in two-dimensional magnets.