Two-dimensional ferroelectric Rashba semiconductors exhibit extraordinary orbital and spin structures. In this research, through first-principle calculations, we demonstrate the ferroelectricity of d1T-phase (distorted 1T-phase) transition-metal dichalcogenide monolayers and realize the manipulation of the Rashba spin-orbit coupling by means of gate voltage. Because of its large composition of out-of-plane atomic orbitals, the rotation of transition metal atoms induced symmetry breaking leads to larger Rashba spin splittings at Γ point of top valence band (560.4 meV Å for WS₂, measured by the first derivative of the energy splitting to the wave vector), and it further increases under a vertical downward electric field and hole doping, which correspond to a positive gate voltage for the constructed device. In comparison, charge doping has a greater effect on Rashba parameters than electric field. These results are of great value to the spin-orbit electronics of two-dimensional materials and their applications in electrically controlled spintronics and memory devices.

二维铁电Rashba 半导体表现出非凡的轨道和自旋结构。在这项研究中，我们通过第一性原理计算证明了 d1T 相（扭曲的 1T 相）过渡金属二硫属化物单层的铁电性，并通过栅极电压实现了对 Rashba 自旋轨道耦合的操纵。由于其平面外原子轨道的大量组成，过渡金属原子的旋转引起的对称破坏导致在顶价带的Γ点处出现更大的 Rashba 自旋分裂（WS ₂为 560.4 meV Å，通过能量分裂为波矢量的一阶导数来测量），并且在垂直向下的电场和空穴掺杂下进一步增加，这对应于构造的器件的正栅极电压。相比之下，电荷掺杂对 Rashba 参数的影响比电场更大。这些结果对二维材料的自旋轨道电子学及其在电控自旋电子学和存储器件中的应用具有重要价值。