We experimentally investigate the effect of electron temperature on transport in the two-dimensional Dirac surface states of the three-dimensional topological insulator HgTe. We find that around the minimal conductivity point, where both electrons and holes are present, heating the carriers with a DC current results in a non-monotonic differential resistance of narrow channels. We show that the observed initial increase in resistance can be attributed to electron-hole scattering, while the decrease follows naturally from the change in Fermi energy of the charge carriers. Both effects are governed dominantly by a van Hove singularity in the bulk valence band. The results demonstrate the importance of interband electron-hole scattering in the transport properties of topological insulators.
@article{arxiv.2106.03435,
title = {Electron-hole scattering limited transport of Dirac fermions in a topological insulator},
author = {Valentin L. Müller and Yuan Yan and Oleksiy Kashuba and Björn Trauzettel and Mohamed Abdelghany and Johannes Kleinlein and Wouter Beugeling and Hartmut Buhmann and Laurens W. Molenkamp},
journal= {arXiv preprint arXiv:2106.03435},
year = {2021}
}