Self-Consistent Model for Gate Control of Narrow-, Broken-, and Inverted-Gap (Topological) Heterostructures
Abstract
Even small electrostatic potentials can dramatically influence the band structure of narrow-, broken-, and inverted-gap materials. A quantitative understanding often necessitates a self-consistent Hartree approach. The valence and conduction band states strongly hybridize and/or cross in these systems. This makes distinguishing between electrons and holes impossible and the assumption of a flat charge carrier distribution at the charge neutrality point hard to justify. Consequently the wide-gap approach often fails in these systems. An alternative is the full-band envelope-function approach by Andlauer and Vogl, which has been implemented into the open-source software package kdotpy (arXiv:2407.12651). We show that this approach and implementation gives numerically stable and quantitatively accurate results where the conventional method fails by modeling the experimental subband density evolution with top-gate voltage in thick (26 nm - 110 nm), topologically inverted HgTe quantum wells. We expect our openly-available implementation to greatly benefit the investigation of narrow-, broken-, and inverted-gap materials.
Keywords
Cite
@article{arxiv.2510.18778,
title = {Self-Consistent Model for Gate Control of Narrow-, Broken-, and Inverted-Gap (Topological) Heterostructures},
author = {Maximilian Hofer and Christopher Fuchs and Moritz Siebert and Christian Berger and Lena Fürst and Martin Stehno and Steffen Schreyeck and Hartmut Buhmann and Tobias Kießling and Wouter Beugeling and Laurens W. Molenkamp},
journal= {arXiv preprint arXiv:2510.18778},
year = {2025}
}