Landau levels in a topological insulator

TL;DR

This paper models the effects of an STM tip on Landau levels in a topological insulator, revealing shifts and suppression of certain Landau levels through solving the 2D Dirac equation with a localized potential.

Contribution

It introduces a theoretical approach to understand how an STM tip influences Landau levels in topological insulators, accounting for electrostatic effects.

Findings

STM tip shifts Landau levels

Suppression of negative Landau levels observed

Model aligns with experimental observations

Abstract

Two recent experiments successfully observed Landau levels in the tunneling spectra of the topological insulator Bi2Se3. To mimic the influence of a scanning tunneling microscope tip on the Landau levels we solve the two-dimensional Dirac equation in the presence of a localized electrostatic potential. We find that the STM tip not only shifts the Landau levels, but also suppresses for a realistic choice of parameters the negative branch of Landau levels.