Spin Susceptibility of an Ultra-Low Density Two Dimensional Electron System

TL;DR

This study measures the spin susceptibility in a low-density 2D electron system in GaAs/AlGaAs, revealing how it varies with density and explaining anomalous g-factors, thus providing insights into electron interactions at ultra-low densities.

Contribution

It provides the first comprehensive measurement of spin susceptibility across a wide density range in a 2D electron system, and introduces an equation modeling its dependence on density and polarization.

Findings

Spin susceptibility increases as density decreases.

The data fits an equation describing density and polarization dependence.

Results explain previously reported anomalous g-factors.

Abstract

We determine the spin susceptibility in a two dimensional electron system in GaAs/AlGaAs over a wide range of low densities from 2$\times10^{9}$cm$^{-2}$ to 4$\times10^{10}$cm$^{-2}$. Our data can be fitted to an equation that describes the density dependence as well as the polarization dependence of the spin susceptibility. It can account for the anomalous g-factors reported recently in GaAs electron and hole systems. The paramagnetic spin susceptibility increases with decreasing density as expected from theoretical calculations.