二维VA族薄膜中的自旋-能谷耦合与外场调控

自旋轨道耦合效应（SOC）将电子的自旋自由度与轨道自由度耦合，是构建自旋电子器件的重要途径。二维黑磷具有独特的物理化学性质，但它没有本征的自旋极化，且SOC较弱，极大地限制了其在自旋电子学中的发展。本项目拟研究二维VA族类黑磷材料（α/β-As、Sb、Bi等）的自旋-能谷效应和外场调控特性。我们将结合密度泛函理论、万尼尔拟合、分子动力学和紧束缚近似等理论计算方法，系统研究这类材料的几何与微观电子结构性质。研究材料的结构与稳定性，分析层间耦合、轨道杂化与几何结构之间的关联；研究多层堆垛与结构相变，探究不同堆垛方式对自旋-能谷耦合的影响；通过外加电场、光场、交换场，以及化学掺杂对电子结构进行调控，揭示内在规律。由于这类材料结构复杂，且结构-稳定性-微观性质内在交织，本项目的系统研究不仅能为新型二维材料的理性设计提供思路，更能为其在自旋电子器件及多场调控方面提供理论依据。

Spin-orbit coupling (SOC), which couples the spin and orbital degrees of freedom, is an important approach to construct spintronic devices. Two-dimensional (2D) black phosphorus, with unique physicochemical properties, has attracted considerable interest in recent years. However, it has no intrinsic spin polarization and the weak SOC strength, severely hindering the future development in spintronics. In this project, we aim to explore 2D VA-group structures beyond black phosphorus, with special attention paid to the spin-valley interaction and property regulation with external fields. By combining density functional theory, Wannier fitting, molecular dynamics and tight-binding modeling, we will systematically investigate the geometric and electronic properties. In particular, we will study the structure and stability, and analyze the correlation between interlayer coupling, orbital hybridization and atomic structure. By exploring multi-layer stacking and structure phase transition, we can understand the effects of stacking order on the spin-valley coupling behaviors. Importantly, we will investigate the regulation of electronic structures by external means, such as electric field, exchange field, light as well as chemical doping. The fundamental mechanism will also be revealed. As this category of materials normally have complicated atomic structures and correlated geometry-stability-electronic property, our detailed studies not only shed light on the rational design of novel 2D structures, but also provide guidance for their potential implementation in spintronic devices and multi-field regulation.