Quantum anomalous Hall state in a fluorinated 1T-MoSe$_2$ monolayer

TL;DR

This paper reports the discovery of a large-gap quantum anomalous Hall state in fluorinated 1T-MoSe2 monolayer, achieved through first-principles calculations, revealing potential for spintronic applications with dissipationless edge channels.

Contribution

The study demonstrates the emergence of a high-Chern-number quantum anomalous Hall state in fluorinated 1T-MoSe2 monolayer, highlighting the role of spin-orbit coupling and chemical functionalization.

Findings

Band gap of 117.2 meV opened by spin-orbit coupling

Chern number of |C|=2 indicating two chiral edge channels

Potential for low-power spintronic devices

Abstract

The quantum anomalous Hall state with a large band gap and a high Chern number is significant for practical applications in spintronics. By performing first-principles calculations, we investigate electronic properties of the fully fluorinated 1T-MoSe$_{2}$ monolayer. Without considering the spin-orbit coupling, the band structure demonstrates single-spin semi-metallic properties and the trigonal warping around $K_{\pm}$ valleys. The introduction of the spin-orbit coupling opens considerable band gaps of $117.2$ meV around the two valleys, leading to a nontrivial quantum anomalous Hall state with a Chern number of $|C|=2$, which provides two chiral dissipationless transport channels from topological edge states and associated quantized anomalous Hall conductivity. In addition, an effective model is constructed to describe the low-energy physics of the monolayer. Our findings in the MoSe$_{2}$F$_{2}$ monolayer sheds light on large-gap quantum anomalous Hall states in two-dimensional materials with the chemical functionalization, and provides opportunities in designing low-power and noise-tolerant spintronic devices.