Impact of Step Defects on Surface States of Topological Insulators

Abstract

The eigenstates in the presence of a step defect (SD) along $x$ or y axis on the surface of topological insulators are exactly solved. It is shown that unlike the electronic states in conventional metals, the topological surface states across the SD can produce spin rotations. The magnitudes of the spin rotations depend on the height and direction of the SD. The oscillations of local density of states (LDOS) are characterized by a wave vector connecting two points on the hexagonal constant-energy contour at higher energies. The period of the oscillation caused by the SD along y axis is $\sqrt{3}$ ($\frac{1}{\sqrt{3}}$) times that induced by the SD along x axis at a larger positive (negative) bias voltage. With increasing the bias voltage, the period of the oscillation, insensitive to the strength of the SD, becomes smaller. At lower energies near the Fermi surface, the two types of wave vectors coexist in the LDOS modulations. These results are consistent qualitatively with recent observations of scanning tunneling microscopy.

4 pages, 4 figures

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• Topological insulators and superconductors
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Transmission of topological surface states through surface barriers
• Observation of Single Dirac Cone Topological Surface State in Compounds TlBiTe2 and TlBiSe2 from a New Topological Insulator Family

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• Anisotropic Fabry-Pérot resonant states confined within nano-steps on the topological insulator surface
• 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${}_3$
• Electron scattering in a superlattice of line defects on the surface of topological insulators
• Proposed Detection of Time Reversal Symmetry in Topological Surface States
• Local density of state oscillations in laterally heterostructured topological insulator-semiconductor systems