The electronic structures of semiconductors and their related transport properties can be tuned via the Rashba effect, which improves thermoelectric performance. The Rashba effect is caused by spin–orbit coupling and breaking of inversion symmetry. Here, we engineer the Rashba effect by constructing two-dimensional (2D) van der Waals heterostructures (vdWHs) Sb/As and Bi/Sb. These break the z-inversion symmetry by removing the reflection along the z-direction, affording Rashba splitting at the top of the valence band. The resulting complex energy bands exhibit enhanced electronic density of states near the band edge and maintain the electrical conductivity. The Sb/As heterostructure has Seebeck coefficients 1.5 times larger than those of the corresponding monolayers, and the Bi/Sb system has an enhanced Seebeck coefficient at high carrier concentrations. Our work demonstrates that 2D vdWHs can be used to induce Rashba splitting with band structure changes that yield favorable thermoelectric properties. This offers a new strategy for designing novel 2D functional materials.

半导体的电子结构及其相关的传输特性可以通过 Rashba 效应进行调整，从而提高热电性能。Rashba 效应是由自旋轨道耦合和反演对称性破坏引起的。在这里，我们通过构建二维 (2D) 范德华异质结构 (vdWHs) Sb/As 和 Bi/Sb 来设计 Rashba 效应。这些通过消除沿z的反射来破坏z反转对称性- 方向，在价带顶部提供 Rashba 分裂。由此产生的复杂能带在能带边缘附近表现出增强的电子态密度并保持导电性。Sb/As异质结构的塞贝克系数是相应单层的1.5倍，Bi/Sb体系在高载流子浓度下具有增强的塞贝克系数。我们的工作表明，二维 vdWH 可用于诱导 Rashba 分裂，其能带结构变化产生有利的热电特性。这为设计新颖的二维功能材料提供了新的策略。