By combining density functional theory with low-energy effective Hamiltonian, we demonstrate strain-engineered electronic and topological properties of the recently synthesized two-dimensional (2D) bismuthene on SiC(0001) substrate. As bismuthene on SiC(0001) exhibits an indirect gap of 0.62 eV with nontrivial topology, we show that the band gap size can be further increased by an applied tensile strain, which follows a nearly linear fashion. Especially, with a tensile strain of 7%, the topological gap can be enhanced to an unprecedented value of 0.83 eV, originating from the different deformation potentials of the conduction band minimum principally contributed from p orbitals of Bi and valance band maximum from the hybridized states of Bi overlayer and SiC substrate. Moreover, we discuss the strength of spin–orbit coupling, in additional to the strain effect, in tuning the electronic structures and topological edge states. Our results suggest the promise of strain engin...

中文翻译：

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SiC（0001）衬底上铋的应变工程电子和拓扑性质

通过将密度泛函理论与低能量有效哈密顿量相结合，我们证明了在SiC（0001）衬底上最近合成的二维（2D）铋的应变工程电子和拓扑特性。由于SiC（0001）上的铋在非平凡的拓扑结构中表现出0.62 eV的间接间隙，因此我们表明，带隙的大小可以通过施加的拉伸应变进一步增加，这几乎遵循线性方式。特别是，在7％的拉伸应变下，拓扑间隙可以提高到前所未有的0.83 eV值，这归因于导带最小的导带的不同形变电势，主要由Bi的p轨道和杂化态的价带最大Bi覆盖层和SiC衬底。此外，我们讨论了自旋轨道耦合的强度，除了应变效应之外，还可以调整电子结构和拓扑边缘状态。我们的结果表明了应变工程的前景。