Temperature-dependent magnetospectroscopy of HgTe quantum wells

TL;DR

This study uses temperature-dependent magnetospectroscopy to analyze HgTe quantum wells, revealing persistent topological insulator signatures at high temperatures and magnetic fields, and demonstrating a method to distinguish topological phases.

Contribution

It provides the first detailed temperature-dependent magnetospectroscopy analysis of HgTe quantum wells, showing topological phase signatures persist at high temperatures and magnetic fields.

Findings

Intra- and inter-band transitions observed in high magnetic fields.

Topological insulator signatures persist at high temperatures.

Magnetospectroscopy effectively distinguishes topological from trivial phases.

Abstract

We report on magnetospectroscopy of HgTe quantum wells in magnetic fields up to 45 T in temperature range from 4.2 K up to 185 K. We observe intra- and inter-band transitions from zero-mode Landau levels, which split from the bottom conduction and upper valence subbands, and merge under the applied magnetic field. To describe experimental results, realistic temperature-dependent calculations of Landau levels have been performed. We show that although our samples are topological insulators at low temperatures only, the signature of such phase persists in optical transitions at high temperatures and high magnetic fields. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases in HgTe quantum wells.