Evidence for electron-electron interaction in topological insulator thin films

TL;DR

This study provides evidence that electron-electron interactions significantly influence quantum transport in topological insulator thin films, highlighting the importance of including interactions in theoretical models.

Contribution

It demonstrates the necessity of considering electron-electron interactions to accurately describe diffusive transport in topological insulator thin films.

Findings

Weak localization observed in transport data

Standard theory fails without electron interactions

Quantum corrections are well explained when interactions are included

Abstract

We consider in our work high quality single crystal thin films of Bi2Se3, grown by molecular beam epitaxy, both with and without Pb doping. Our ARPES data demonstrate topological surface states with a Fermi level lying inside the bulk band gap in the Pb doped filims. Transport data show weak localization behavior, as expected for a 2D system, but a detailed analysis within the standard theoretical framework of diffusive transport shows that the temperature and magnetic field dependences of resistance cannot be reconciled in a theory that neglects inter-electron interactions. We demonstrate that an excellent account of quantum corrections to conductivity is achieved when both disorder and interaction are taken into account. These results clearly demonstrate that it is crucial to include electron electron interaction for a comprehensive understanding of diffusive transport in topological insulators.