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arXiv · 0912.4477

Scattering from Surface Step Edges in Strong Topological Insulators

Rudro R. Biswas·Alexander V. Balatsky
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Abstract

We study the characteristics of scattering processes at step edges on the surfaces of Strong Topological Insulators (STI), arising from restrictions imposed on the $S$-matrix \emph{solely} by time reversal symmetry and translational invariance along the step edge. We show that the `perfectly reflecting' step edge that may be defined with these restrictions allow modulations in the Local Density of States (LDOS) near the step edge to decay no slower than $1/x$, where $x$ is the distance from the step edge. This is faster than in 2D Electron Gases (2DEG) --- where the LDOS decays as $1/\sqrt{x}$ --- and shares the same cause as the suppression of backscattering in STI surface states. We also calculate the scattering at a delta function scattering potential and argue that \emph{generic} step edges will produce a $x^{-3/2}$ decay of LDOS oscillations. Experimental implications are also discussed.

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Rudro R. Biswas, Alexander V. Balatsky. 2010-03-29. Scattering from Surface Step Edges in Strong Topological Insulators. https://doi.org/10.1103/physrevb.83.075439

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