Large-Gap Quantum Anomalous Hall Effect in Monolayer Halide Perovskite

TL;DR

This paper predicts stable monolayer halide perovskites that exhibit large-gap quantum anomalous Hall effects at high temperatures, offering promising materials for spintronics and topological quantum computing.

Contribution

It introduces a new family of monolayer halide perovskites with large band gaps and high-temperature quantum anomalous Hall effects, expanding the material options for topological electronics.

Findings

Monolayer halide perovskites are structurally stable and half-metallic.

Large band gaps (63-103 meV) enable quantum anomalous Hall effect.

High transition temperatures (>248 K) suggest practical applications.

Abstract

We theoretically propose a family of structurally stable monolayer halide perovskite A$_3$B$_2$C$_9$ (A=Rb, Cs; B=Pd, Pt; C=Cl, Br) with easy magnetization planes. These materials are all half-metals with large spin gaps over 1~eV accompanying with a single spin Dirac point located at K point. When the spin-orbit coupling is switched on, we further show that Rb$_3$Pt$_2$Cl$_9$, Cs$_3$Pd$_2$Cl$_9$, and Cs$_3$Pt$_2$Cl$_9$ monolayers can open up large band gaps from 63 to 103 meV to harbor quantum anomalous Hall effect with Chern numbers of $\mathcal{C}=\pm1$, whenever the mirror symmetry is broken by the in-plane magnetization. The corresponding Berezinskii-Kosterlitz-Thouless transition temperatures are over 248~K. Our findings provide a potentially realizable platform to explore quantum anomalous Hall effect and spintronics at high temperatures.