Ab-initio transport across Bismuth Selenide surface barriers

Abstract

We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi${}_2$Se${}_3$(111) topological surface states by means of large-scale ab-initio transport simulations. Our results demonstrate the suppression of perfect backscattering, while all other scattering processes, which do not entail a complete spin and momentum reversal, are allowed. Furthermore, we find that the spin of the surface state develops an out of plane component as it traverses the barrier. Our calculations reveal the existence of quasi-bound states in the vicinity of the surface barriers, which appear in the form of an enhanced density of states in the energy window corresponding to the topological state. For double barriers we demonstrate the formation of quantum well states. To complement our first-principles results we construct a two-dimensional low-energy effective model and show that band bending plays a significant role in the scattering process. Our findings are discussed in the context of a number of recent experimental works.

arXiv commentUpdated text, published version

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Cited by in corpus (8)

• Nonequilibrium spin texture within a thin layer below the surface of current-carrying topological insulator Bi${}_2$Se${}_3$: A first-principles quantum transport study
• Quantum transport simulation scheme including strong correlations and its application to organic radicals adsorbed on gold
• A tight-binding model for the band dispersion in rhombohedral topological insulators over the whole Brilluoin zone
• Spin-orbit induced equilibrium spin currents in materials
• Single atom anisotropic magnetoresistance on a topological insulator surface
• Intrinsic surface dipole in topological insulators
• Numerical analysis of surface and edge states in slabs, stripes, rods and surface steps of topological insulators
• Experimental Observation of Bound States of 2D Dirac Electrons at Surface Steps of the Topological Insulator Bi${}_2$Se${}_3$