Bending Strain Engineering of Spin Transport in Quantum Spin Hall Systems: Topological Nano-mechanospintronics

Abstract

Quantum spin Hall (QSH) system can exhibit exotic spin transport phenomena, mediated by its topological edge states. Here a novel concept of bending strain engineering to tune the spin transport properties of a QSH system is demonstrated by both model and first-principles calculations. Interestingly, we discover that bending strain can be used to mitigate the spin conservation of a QSH system to generate a non-zero spin current (SC), meanwhile the preservation of time reversal symmetry renders its edge states topologically protected to transport robust SC without back scattering. This novel physics mechanism can be applied to effectively tune the SC and spin Hall current in a QSH system by control of its bending curvature. Furthermore, the realization of QSH systems with controllable curvature can be achieved by the concept of "topological nanomechnical architecture". Taking Bi/Cl/Si(111) as a material example, we demonstrate that the relative spin orientations between two edge states of a Bi/Cl/Si(111) film can indeed be tuned dramatically by its self-bending behaviors induced by the pre-designed inherent strain. Therefore, this concept of "bending strain engineering of spins" via topological nanomechanical architecture affords a promising route towards the realization of topological nano-mechanospintronics.

arXiv comment5 figures

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Cited by in corpus (8)

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• Layertronic control of topological states in multilayer metal-organic frameworks
• Twist-resilient and robust ferroelectric quantum spin Hall insulators driven by van der Waals interactions
• A Unified Theory and Fundamental Rules of Strain-dependent Doping Behaviors in Semiconductors
• Twist-induced magnon Landau levels in honeycomb magnets
• Tuning topology in thin films of topological insulators by strain gradients
• Quantum mechanics of fermion confined to a curved surface in Foldy-Wouthuysen representation