Probing temperature-driven flow lines in a gated two-dimensional electron gas with tunable spin-splitting

TL;DR

This study investigates how temperature influences the flow of conductivities in a gated GaAs 2DEG with tunable spin-splitting, confirming theoretical predictions about critical Hall conductivity variations.

Contribution

It provides experimental validation of a modular symmetry-based theory predicting the relationship between spin-splitting and critical Hall conductivity in 2DEGs.

Findings

Experimental data support the theory's predictions.

Spin-resolved and spin-degenerate phase transitions observed.

Critical Hall conductivity varies with spin-splitting as predicted.

Abstract

We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able to tune the 2DEG density and thus vary disorder and spin-splitting. Data for both the spin-resolved and spin-degenerate phase transitions are presented, the former collapsing to the latter with decreasing gate voltage and/or decreasing spin-splitting. The experimental results support a recent theory, based on modular symmetry, which predicts how the critical Hall conductivity varies with spin-splitting.