Quantization of entropy in a quasi-two-dimensional electron gas

TL;DR

This paper shows that the partial entropy of a 2D electron gas exhibits quantized peaks at certain resonances, revealing a topological phase transition and how disorder affects these peaks.

Contribution

It introduces the quantization of partial entropy as a signature of topological phase transitions in a 2DEG, independent of material parameters.

Findings

Quantized peaks in partial entropy at electron level resonances

Dependence of peak magnitude on disorder and temperature

Identification of topological phase transition signature

Abstract

We demonstrate that the partial entropy of a two-dimensional electron gas (2DEG) exhibits quantized peaks at resonances between the chemical potential and electron levels of size quantization. In the limit of no scattering, the peaks depend only on the subband quantization number and are independent on material parameters, shape of the confining potential, electron effective mass and temperature. The quantization of partial entropy is a signature of a topological phase transition in a 2DEG. In the presence of stationary disorder, the magnitude of peaks decreases. Its deviation from the quantized values is a direct measure of the disorder induced smearing of the electronic density of states.