Theoretical investigation of Quantum Anomalous Hall Effect in Potassium Tri-vanadium Pentantimonide

TL;DR

This theoretical study explores the potential for realizing the quantum anomalous Hall effect in Potassium Tri-vanadium Pent-antimonide through complex band structure analysis and topological characteristics, suggesting possible experimental tuning methods.

Contribution

It introduces a detailed theoretical model incorporating various interactions to predict the emergence of quantized anomalous Hall effect in the material.

Findings

Multiple bands with nontrivial Berry curvature are identified.

Opposite Chern numbers in two bands suggest chiral edge states.

System shows signs of weak topological characteristics.

Abstract

The Kagome metal Potassium Tri-vanadium Pent-antimonide can support the quantum anomalous Hall effect theoretically. This is justified by flat bands and Dirac points susceptible to gap opening by spin-orbit coupling or magnetic ordering. The theoretical investigation of this quantum effect is possible exploring strategies like magnetic proximity, and strain or electric gating tuning. Our goal here is to explore the possibility of quantum anomalous Hall effect with a system Hamiltonian involving nearest-neighbour and complex next nearest-neighbour hopping, Rashba spin-orbit coupling, exchange field due to magnetic proximity, and charge density wave. Our preliminary analysis with these ingredients reveals that the system hosts multiple bands whose Chern numbers values suggest weak topological characteristics-not yet quantized, but showing signs of nontrivial Berry curvature accumulation. Upon introducing momentum-space winding, mimicking an orbital magnetic flux, through the momentum-dependence of the phase of the complex hopping, we find that two bands in the multiple band system carry opposite Chern numbers, indicating the emergence of chiral edge states and a quantized anomalous Hall effect. The rest remain trivial, but the system as a whole is no longer topologically inert.