Spin dynamics of a quasi-one-dimensional electron in the quantum limit

TL;DR

This study investigates electron spin dynamics in a quasi-one-dimensional system, revealing a double-peak nuclear spin relaxation profile linked to electron-electron interactions, deviating from non-interacting models.

Contribution

It provides experimental and theoretical evidence of interaction-induced features in spin relaxation in quantum point contacts, a novel insight into low-dimensional electron systems.

Findings

Double-peak structure in nuclear spin relaxation rate below the lowest subband

Deviation from non-interacting electron model predictions

Enhanced electron-electron interactions likely cause observed phenomena

Abstract

We study electron spin dynamics whose movement is restricted to the lowest one dimensional subband channel ($G \le 2e^2/h $), through nuclear spin relaxation rate measurement ($1/T_1$). We observe an unusual double-peak structure in the $1/T_1$ profile below the lowest subband level, where the up and down spin edge channel is still largely overlap. This profile significantly deviates from the behavior predicted by a non-interacting electron model, in which the only source of relaxation is through thermal fluctuations near the Fermi level. Our experimental results, supported by theoretical calculations, suggest that enhanced electron-electron interactions at the center of a quantum point contact are the likely origin of the observed double-peak structures.