Enhanced Intrinsic Anomalous Valley Hall Effect Induced by Spin–Orbit Coupling in MXene Monolayer M<sub>3</sub>N<sub>2</sub>O<sub>2</sub> (M = Y, La)
Jiajun Lu, Ran Liu, Fang-Yu Yue, Xiuwen Zhao, Guichao Hu, Xiaobo Yuan, Junfeng Ren
Abstract
The limitation of suitable anomalous valley Hall effect (AVHE) materials has seriously hindered the booming development and the widespread application of valleytronics. Here, through the first-principles calculations, we propose a MXene monolayer Y3N2O2 with spontaneous valley polarization (VP) of 21.3 meV, which induces intrinsic AVHE. The VP can be modulated linearly, which provides a route of effective control of the valley signals. Importantly, VP can be enhanced by adjusting up the spin–orbit coupling (SOC) based on a SOC Hamiltonian model and the first-principles calculations. From this physics underlying, we substitute the Y atom with the La atom and further propose the monolayer La3N2O2, in which the heavy atom La will provide stronger SOC than Y atom. The spontaneous VP in La3N2O2 is enhanced to 100.4 meV, so AVHE can be easily achieved. Our work not only provides compelling candidates for AVHE materials but also offers a novel mindset for finding suitable valleytronic devices.