Symmetry in the insulator - quantum Hall - insulator transitions observed in a Ge/SiGe quantum well

TL;DR

This study investigates the symmetry of insulator-quantum Hall-insulator transitions in a Ge/SiGe quantum well, revealing similar transport properties and energy scales for transitions at different magnetic fields.

Contribution

It provides experimental evidence of symmetric behavior in insulator-quantum Hall-insulator transitions, highlighting the comparable transport characteristics and energy scales involved.

Findings

Direct transitions between insulators and the $ u=1$ quantum Hall state observed.

Transitions exhibit similar transport properties at different magnetic fields.

The characteristic energy scale for high field transition is larger.

Abstract

We examine the magnetic field driven insulator-quantum Hall-insulator transitions of the two dimensional hole gas in a Ge/SiGe quantum well. We observe direct transitions between low and high magnetic field insulators and the $\nu=1$ quantum Hall state. With increasing magnetic field, the transitions from insulating to quantum Hall and quantum Hall to insulating are very similar with respect to their transport properties. We address the temperature dependence around the transitions and show that the characteristic energy scale for the high field transition is larger.