Pressure and temperature driven phase transitions in HgTe quantum wells

TL;DR

This paper theoretically investigates how pressure and temperature influence phase transitions in HgTe quantum wells, revealing the ability to switch between different electronic phases through external tuning.

Contribution

It provides a detailed theoretical analysis of pressure and temperature effects on phase transitions in HgTe quantum wells using an 8-band p Hamiltonian.

Findings

Pressure and temperature can induce transitions between semimetal, band insulator, and topological insulator phases.

Band inversion can be accompanied by non-local band overlap under certain conditions.

Phase diagrams for pressure and temperature effects are constructed.

Abstract

We present theoretical investigations of pressure and temperature driven phase transitions in HgTe quantum wells grown on CdTe buffer. Using the 8-band \textbf{k$\cdot$p} Hamiltonian we calculate evolution of energy band structure at different quantum well width with hydrostatic pressure up to 20 kBar and temperature ranging up 300 K. In particular, we show that in addition to temperature, tuning of hydrostatic pressure allows to drive transitions between semimetal, band insulator and topological insulator phases. Our realistic band structure calculations reveal that the band inversion under hydrostatic pressure and temperature may be accompanied by non-local overlapping between conduction and valence bands. The pressure and temperature phase diagrams are presented.