Surface Scattering via Bulk Continuum States in the 3D Topological Insulator Bi$_{2}$Se$_{3}$

TL;DR

This study uses STM and $dI/dV$ mapping to reveal that electron interference on Bi$_{2}$Se$_{3}$ surfaces occurs via scattering between surface states and bulk continuum states, challenging the belief of suppressed backscattering.

Contribution

It demonstrates that electron scattering involves bulk continuum states in Bi$_{2}$Se$_{3}$, providing new insights into surface-bulk interactions in topological insulators.

Findings

Electron interference occurs near the Dirac node.

Scattering involves both surface states and bulk continuum states.

Backscattering suppression is not complete in the bulk gap.

Abstract

We have performed scanning tunneling microscopy and differential tunneling conductance ($dI/dV$) mapping for the surface of the three dimensional topological insulator Bi$_{2}$Se$_{3}$. The fast Fourier transformation applied to the $dI/dV$ image shows an electron interference pattern near Dirac node despite the general belief that the backscattering is well suppressed in the bulk energy gap region. The comparison of the present experimental result with theoretical surface and bulk band structures shows that the electron interference occurs through the scattering between the surface states near the Dirac node and the bulk continuum states.