Quantum Anomalous Hall and Valley Quantum Anomalous Hall Effects in Two-Dimensional d0 Orbital XY Monolayers

TL;DR

This paper introduces a new class of two-dimensional d0 orbital XY monolayers exhibiting quantum anomalous Hall effects and valley properties, with tunable topological features via strain, promising for spintronics and topological devices.

Contribution

The study proposes a new family of XY monolayers with novel topological and valley properties, including strain-tunable quantum anomalous Hall effects.

Findings

Several XY monolayers exhibit quantum anomalous Hall effect.

CsSb monolayer shows valley quantum anomalous Hall effect with large splitting.

Topological properties can be tuned by in-plane strain.

Abstract

We propose a new family of the d0 orbital XY (X = K, Rb, Cs; Y = N, P, As, Sb, Bi) monolayers with abundant and novel topology and valley properties. The KN, RbN, RbP, RbAs, CsP, CsAs, and CsSb monolayers possess remarkable quantum anomalous Hall effect (QAHE). CsSb monolayer also exhibits extraordinary valley QAHE with giant splitting. Moreover, the topological properties of XY monolayers can be effciently tuned by the in-plane strain, owing to the strain-induced band inversion between the px;y and pz orbitals. Our findings suggest that the d0 orbital XY monolayers can be good candidates for promising applications in the spintronics and multifunctional topological-based devices.