Gentile Paola, Cuoco Mario, Ortix Carmine
CNR-SPIN and Dipartimento di Fisica "E. R. Caianiello", Università degli Studi di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Salerno), Italy.
Institute for Theoretical Solid State Physics, IFW-Dresden, Helmholtzstraße 20, D-01069 Dresden, Germany.
Phys Rev Lett. 2015 Dec 18;115(25):256801. doi: 10.1103/PhysRevLett.115.256801. Epub 2015 Dec 16.
We prove that curvature effects in low-dimensional nanomaterials can promote the generation of topological states of matter by considering the paradigmatic example of quantum wires with Rashba spin-orbit coupling, which are bent in a nanoscale periodic serpentine structure. The effect of the periodic curvature generally results in the appearance of insulating phases with a corresponding novel butterfly spectrum characterized by the formation of finite measure complex regions of forbidden energies. When the Fermi energy lies in the gaps, the system displays localized end states protected by topology. We further show that for certain superstructure periods the system possesses topologically nontrivial insulating phases at half filling. Our results suggest that the local curvature and the topology of the electronic states are inextricably intertwined in geometrically deformed nanomaterials.
通过考虑具有Rashba自旋轨道耦合的量子线这一典型例子，我们证明了低维纳米材料中的曲率效应可以促进物质拓扑态的产生，这些量子线被弯曲成纳米级周期性蛇形结构。周期性曲率的影响通常会导致绝缘相的出现，其具有相应的新型蝴蝶谱，其特征是形成有限测度的禁能复区域。当费米能位于能隙中时，系统显示出受拓扑保护的局域端态。我们进一步表明，对于某些超结构周期，系统在半填充时具有拓扑非平凡绝缘相。我们的结果表明，在几何变形的纳米材料中，局部曲率与电子态的拓扑结构紧密相连。
