Two-dimensional ferrovalley materials, which simultaneously exhibit ferromagnetism and valley polarization, have garnered substantial interest in recent years due to their fascinating physical properties and potential applications. However, the ferrovalley materials currently discovered are predominantly based on d orbitals. In this work, using first-principles calculations, we predict an exceptionally rare p-orbital-dependent ferrovalley characteristic in the MXene Lu3N2O2 monolayer. The monolayer shows intrinsic ferromagnetism contributed by the N-2p orbital with a magnetic moment of 1μB/u.c. Such 2p magnetism can be interpreted by the double exchange coupling between N anions mediated by the middle Lu cation. Owing to the simultaneous breaking of spatial inversion symmetry and time-reversal symmetry, the out-of-plane magnetization and spin–orbit coupling result in a sizable valley polarization of 80.93 meV in the conduction band for the monolayer. Notably, the energy dispersions that exhibit valley polarization are chiefly governed by the N-2p orbital, accompanied by a high Fermi velocity and a small effective electron mass. The demonstrated valley contrasting Berry curvature ensures that the monolayer can give rise to the anomalous valley Hall effect (AVHE) through electron doping, with the doping concentration evaluated in the range of 0.02–0.08 e/u.c. In addition to effectively modulating the magnitude of valley polarization, biaxial strain can also trigger the self-doping phenomenon, thereby enabling the monolayer to generate the AVHE independently of external electron doping. Our findings provide a more promising platform for valleytronic applications and significantly enrich the ferrovalley material family.

中文翻译：

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MXene Lu3N2O2 中 p 轨道依赖性铁谷特征


二维 ferrovalley 材料同时表现出铁磁性和谷极化，由于其迷人的物理性质和潜在的应用，近年来引起了人们的极大兴趣。然而，目前发现的 ferrovalley 材料主要基于 d 轨道。在这项工作中，使用第一性原理计算，我们预测了 MXene Lu3N2O2 单层中异常罕见的 p 轨道依赖性铁谷特征。单层显示出由 N-2p 轨道贡献的固有铁磁性，磁矩为 1μB/u.c。这种 2p 磁性可以通过中间 Lu 阳离子介导的 N 阴离子之间的双交换耦合来解释。由于空间反转对称性和时间反转对称性同时被打破，面外磁化和自旋-轨道耦合导致单层导带中产生 80.93 meV 的相当大的谷极化。值得注意的是，表现出谷极化的能量色散主要由 N-2p 轨道控制，伴随着高费米速度和小有效电子质量。所证明的谷对比 Berry 曲率确保单层可以通过电子掺杂产生异常谷霍尔效应 （AVHE），评估的掺杂浓度在 0.02–0.08 e/u.c. 的范围内。除了有效调节谷极化的大小外，双轴应变还可以触发自掺杂现象，从而使单层能够独立于外部电子掺杂产生 AVHE。我们的发现为 valleytronic 应用提供了一个更有前途的平台，并显着丰富了 ferrovalley 材料家族。