Possible evidence of a spontaneous spin-polarization in mesoscopic 2D electron systems

TL;DR

This study provides experimental evidence suggesting spontaneous spin polarization in low-density mesoscopic 2D electron systems, revealed through conductance measurements and their behavior under magnetic fields and varying conditions.

Contribution

The paper presents the first experimental indication of spontaneous spin polarization in mesoscopic 2D electron systems at zero magnetic field.

Findings

Double-peak conductance structure near Fermi energy observed

Peaks' behavior under magnetic field links to opposite spin states

Splitting persists across temperature and disorder variations

Abstract

We have experimentally studied the non-equilibrium transport in low-density clean 2D electron systems at mesoscopic length scales. At zero magnetic field (B), a double-peak structure in the non-linear conductance was observed close to the Fermi energy in the localized regime. From the behavior of these peaks at non-zero B, we could associate them to the opposite spin states of the system, indicating a spontaneous spin polarization at B = 0. Detailed temperature and disorder dependence of the structure shows that such a splitting is a ground state property of the low-density 2D systems.