First-principles prediction of quantum anomalous Hall effect in two-dimensional Co₂Te lattice

Abstract

The quantum anomalous Hall effect (QAHE) has special quantum properties that are ideal for possible future spintronic devices. However, the experimental realization is rather challenging due to its low Curie temperature and small non-trivial bandgap in two-dimensional (2D) materials. In this paper, we demonstrate through first-principles calculations that monolayer Co2Te material is a promising 2D candidate to realize QAHE in practice. Excitingly, through Monte Carlo simulations, it is found that the Curie temperature of single-layer Co2Te can reach 573K. The band crossing at the Fermi level in monolayer Co2Te is opened when spin-orbit coupling is considered, which leads to QAHE with a sizable bandgap of E g = 96 meV, characterized by the non-zero Chern number (C = 1) and a chiral edge state. Therefore, our findings not only enrich the study of quantum anomalous Hall effect, but also broaden the horizons of the spintronics and topological nanoelectronics applications.

Design of sign-reversible Berry phase effect in 2D magneto-valley material

“…Furthermore, considering the perspective of potential applications in valleytronics, except for AVHE, the exploration for magneto-valley materials with valley-related multiple Hall effect (MHE) is of significant importance, which can enrich the valley-related physics and emerging quantum states of matter. One exotic valley-related multiple Hall effect is the quantum anomalous valley Hall effect (QAVHE), [36][37][38][39][40] which possesses the interplay between valley and band topology and combines the valley index and quantum anomalous Hall effect (QAHE), [36] making it possible to realize high-performance quantum devices and thus raising an intensive interest in materials science. However, the realization of QAVHE [37] relies on the combination of SOC, band topology and magnetic ordering, which pose a great challenge for the research on potential high-performance valley-controllable quantum computational devices in 2D materials.…”