Spin Susceptibility of a 2D Electron System in GaAs towards the Weak Interaction Region

TL;DR

This study measures the spin susceptibility of a high-quality 2D electron system in GaAs/AlGaAs, revealing a monotonic decrease with increasing density and aligning with theoretical predictions in the weak interaction regime.

Contribution

It provides the first detailed experimental measurement of spin susceptibility in the weak interaction regime of a 2D electron system, accounting for band structure effects.

Findings

Spin susceptibility decreases from 3 to 1.1 as density increases.

Results agree with recent theoretical models at high density.

Band structure effects are significant at large electron densities.

Abstract

We determine the spin susceptibility $\chi$ in the weak interaction regime of a tunable, high quality, two-dimensional electron system in a GaAs/AlGaAs heterostructure. The band structure effects, modifying mass and g-factor, are carefully taken into accounts since they become appreciable for the large electron densities of the weak interaction regime. When properly normalized, $\chi$ decreases monotonically from 3 to 1.1 with increasing density over our experimental range from 0.1 to $4\times10^{11} cm^{-2}$. In the high density limit, $\chi$ tends correctly towards $\chi\to 1$ and compare well with recent theory.