Electron scattering in a superlattice of line defects on the surface of topological insulators

TL;DR

This paper theoretically investigates how periodic line defects on topological insulator surfaces affect electron scattering, revealing energy-dependent transmission resonances and potential for controlling electronic properties.

Contribution

It introduces a transfer matrix method analysis of electron scattering by line defects considering hexagonal warping effects, highlighting directional dependence and energy-specific phenomena.

Findings

Transmission resonances depend on defect number and potential strength.

High conductance persists at low energies despite defects.

Surface ripples can be used to manipulate electronic properties.

Abstract

The electron scattering from periodic line defects on the surface of topological insulators with hexagonal warping effect is investigated theoretically by means of a transfer matrix method. The influence of surface line defects, acting as structural ripples on propagation of electrons are studied in two perpendicular directions due to the asymmetry of warped energy contour under momentum exchange. The transmission profiles and the details of resonant peaks which vary with the number of defects and the strength of their potentials are strongly dependent on the direction in which the line defects extend. At low energies, the quantum interference between the incident and reflected propagating electrons has the dominant contribution in transmission resonances, while at high energies the multiple scattering processes on the constant-energy contour also appear because of the strong warping effect. By increasing the spatial separation between the line defects, the minimum value of electrical conductance remains significantly high at low incident energies, while the minimum value may approach zero at high energies as the number of defects is increased. Our findings suggest that the potential ripples on the surface of topological insulators can be utilized to control the local electronic properties of these materials.