Spin susceptibility of two-dimensional electrons in narrow AlAs quantum wells

TL;DR

This study measures the spin susceptibility of dilute two-dimensional electrons in a narrow AlAs quantum well, revealing an enhancement that aligns with quantum Monte Carlo predictions and persists through the metal-insulator transition.

Contribution

It provides the first measurements of spin susceptibility in a single-valley 2D electron system in AlAs quantum wells, confirming theoretical predictions.

Findings

Spin susceptibility increases as electron density decreases.

Enhancement of spin susceptibility matches quantum Monte Carlo calculations.

Susceptibility remains finite across the metal-insulator transition.

Abstract

We report measurements of the spin susceptibility in dilute two-dimensional electrons confined to a 45$\AA$ wide AlAs quantum well. The electrons in this well occupy an out-of-plane conduction-band valley, rendering a system similar to two-dimensional electrons in Si-MOSFETs but with only one valley occupied. We observe an enhancement of the spin susceptibility over the band value that increases as the density is decreased, following closely the prediction of quantum Monte Carlo calculations and continuing at finite values through the metal-insulator transition.