Destabilization of the 2D conducting phase by an in-plane magnetic field

TL;DR

This paper investigates how an in-plane magnetic field destabilizes the 2D conducting phase in low-density electrons by promoting spin polarization and localization, using a self-consistent theoretical approach.

Contribution

It introduces a self-consistent memory function formalism to analyze the effects of disorder and exchange-correlation in spin-polarized 2D electron systems under magnetic fields.

Findings

Fully spin polarized state suppresses conduction.

Critical magnetic field for polarization depends on carrier density.

Phase diagram shows transition between metallic and insulating states.

Abstract

We propose a mechanism for the recently reported destabilization by an in-plane magnetic field of the conducting phase of low density electrons in 2D. We apply our self-consistent approach based on the memory function formalism to the fully spin polarized electron system. This takes into account both disorder and exchange-correlation effects. We show that spin polarization significantly favors localization because of the enhancement of the exchange-correlations. A key outcome is that the conducting phase for the fully spin polarized system is significantly suppressed. The in-plane magnetic field needed to stabilize the fully spin polarized state lies in the range 0.1<H<1 T, depending on the carrier density. We determine the metal-insulator phase diagram for the unpolarized and fully polarized systems, and we estimate the dependence of the critical magnetic field on carrier density.