Manipulation of the valley degree of freedom provides a new path for quantum information technology, but the real intrinsic large valley-polarization materials are few reported up to date. Here, we perform first-principles calculations to predict a class of 2H-phase single layer (SL) materials LuX
2 (X=Cl, Br, I) to be ideal candidates. SL-LuX
2 are ferrovalley materials with a giant valley-polarization of 55~148 meV as a result of its large spin-orbital coupling (SOC) and intrinsic ferromagnetism (FM). The magnetic transition temperatures of SL-LuI2 and SL-LuCl2 are estimated to be 89~124K, with a sizable magnetic anisotropy with out-of-plane direction. Remarkably, the anomalous valley Hall effect (AVHE) can be controlled in SL-LuX
2 when an external electric field is applied. Moreover, the intrinsic valley-polarization of SL-LuI2 is highly robust for biaxial strain. These findings provide a promising ferrovalley material system for the experiment of valleytronics and the subsequent application.
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.
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