Magnetism near the metal-insulator transition in two-dimensional electron systems: the role of interaction and disorder

TL;DR

This paper investigates how electron interactions and disorder influence magnetism near the metal-insulator transition in 2D electron systems, revealing correlations between magnetic properties and electronic compressibility through density functional calculations.

Contribution

It provides a theoretical analysis linking magnetic susceptibility, compressibility, and the metal-insulator transition in 2D electron gases considering disorder effects.

Findings

Correlation between inverse capacitance minimum and magnetic susceptibility maximum

Magnetization peaks coincide with the metal-insulator transition point

Inverse participation ratio supports the transition point identification

Abstract

Recent thermodynamic measurements on two-dimensional (2D) electron systems have found diverging behavior in the magnetic susceptibility and appearance of ferromagnetism with decreasing electron density. The critical densities for these phenomena coincide with the metal-insulator transition recorded in transport measurements. Based on density functional calculations within the local spin-density approximation, we have investigated the compressibility and magnetic susceptibility of a 2D electron gas in the presence of remote impurities. A correlation between the minimum in the inverse capacitance ($\partial\mu /\partial n$) and the maximum of magnetization and magnetic susceptibility is found. Based on values we obtain for the inverse participation ratio, this seems to be also the MIT point.