Berry-phase switch in electrostatically-confined topological surface states

TL;DR

This study demonstrates electrostatic trapping of topological surface states in Sb2Te3 films and observes a Berry-phase switch, offering new possibilities for topological insulator-based quantum devices.

Contribution

It provides the first visualization of trapping topological surface states in circular n-p junctions and confirms Berry-phase switching through experimental and simulation comparison.

Findings

Trapped resonances show field-induced splittings at zero magnetic field.

Berry-phase switch behavior is confirmed by experimental and simulation data.

Electrostatic trapping of topological states is successfully achieved in epitaxial films.

Abstract

Here we visualize the trapping of topological surface states in the circular n-p junctions on the top surface of the 7-quintuple-layer three dimensional (3D) topological insulator (TI) Sb2Te3 epitaxial films. As shown by spatially- and field-dependent tunneling spectra, these trapped resonances show field-induced splittings between the degenerate time-reversal-symmetric states at zero magnetic field. These behaviors are attributed unambiguously to Berry-phase switch by comparing the experimental data with both numerical and semi-classical simulations. The successful electrostatic trapping of topological surface states in epitaxial films and the observation of Berry-phase switch provide a rich platform of exploiting new ideas for TI-based quantum devices.