Chern Number Tunable Quantum Anomalous Hall Effect in Monolayer Transitional Metal Oxides via Manipulating Magnetization Orientation

TL;DR

This paper proposes a theoretical method to realize and control the quantum anomalous Hall effect with tunable Chern numbers in monolayer transition metal oxides by manipulating magnetization orientation, potentially enabling high-temperature applications.

Contribution

It introduces NiAsO$_3$ and PdSbO$_3$ monolayers as new materials for tunable QAHE with different Chern numbers based on magnetization direction control.

Findings

Low-Chern-number phase with $ ext{C}= ext{±}1$ when magnetization is in-plane.

High-Chern-number phase with $ ext{C}= ext{±}3$ when magnetization has a z-component.

Global band gap in PdSbO$_3$ approaches room temperature energy scale (23.4 meV).

Abstract

Although much effort has been made to explore quantum anomalous Hall effect (QAHE) in both theory and experiment, the QAHE systems with tunable Chern numbers are yet limited. Here, we theoretically propose that NiAsO$_3$ and PdSbO$_3$, monolayer transitional metal oxides, can realize QAHE with tunable Chern numbers via manipulating their magnetization orientations. When the magnetization lies in the \textit{x-y} plane and all mirror symmetries are broken, the low-Chern-number (i.e., $\mathcal{C}=\pm1$) phase emerges. When the magnetization exhibits non-zero \textit{z}-direction component, the system enters the high-Chern-number (i.e., $\mathcal{C}=\pm3$) phase, even in the presence of canted magnetization. The global band gap can approach the room-temperature energy scale in monolayer PdSbO$_3$ (23.4 meV), when the magnetization is aligned to \textit{z}-direction. By using Wannier-based tight-binding model, we establish the phase diagram of magnetization induced topological phase transition. Our work provides a high-temperature QAHE system with tunable Chern number for the practical electronic application.