Thermodynamic magnetization of two-dimensional electron gas measured over wide range of densities

TL;DR

This study measures the magnetization derivative of a two-dimensional electron gas across a wide density range, revealing nonlinear behavior indicative of strong electron coupling in Si-MOSFETs.

Contribution

It extends the density range of dm/dn measurements in 2D electron gases and analyzes the nonlinear magnetization behavior at low temperatures.

Findings

Nonlinear dm/dn observed at low temperatures in both metallic and dielectric regions.

Strong coupling between itinerant and localized electrons suggested by nonlinear behavior.

Measurements cover a broader density range than previous studies.

Abstract

We report measurements of dm/dn in Si MOSFET, where m is the magnetization of the two-dimensional electron gas and n is its density. We extended the density range of measurements from well in the metallic to deep in the insulating region. The paper discusses in detail the conditions under which this extension is justified, as well as the corrections one should make to extract dm/dn properly. At low temperatures, dm/dn was found to be strongly nonlinear already in weak magnetic fields, on a scale much smaller than the characteristic scales, expected for interacting two-dimensional electron gas. Surprisingly, this nonlinear behavior exists both in the dielectric, and in the metallic region. These observations, we believe, provide evidence for strong coupling of the itinerant and localized electrons in Si-MOSFET.