Spin-dependent transport in a clean one-dimensional channel

TL;DR

This study investigates the 0.7 conductance anomaly in clean one-dimensional channels, revealing its persistence under varying confinement and its independence from transmission effects, thus providing insights into its underlying physics.

Contribution

The paper introduces a novel 1D channel design with overlaying gates and demonstrates the robustness of the 0.7 structure against changes in confinement and series configurations.

Findings

0.7 structure persists under doubled confinement strength

The 0.7 structure in series channels behaves like a single channel

The 0.7 structure is not due to ballistic transmission effects

Abstract

A shoulder-like feature close to $(0.7\times 2e^{2}/h)$, "the 0.7 structure" at zero magnetic field was observed in clean one-dimensional (1D) channels [K.J. Thomas et al., Phys. Rev. Lett. 77, 135 (1996)]. To provide further understanding of this structure, we have performed low-temperature measurements of a novel design of 1D channel with overlaying finger gates to study the 0.7 structure as a function of lateral confinement strength and potential profile. We found that the structure persists when the lateral confinement strength is changed by a factor of 2. We have also shown that the 0.7 structure present in two 1D channels in series behaves like a single 1D channel which shows the 0.7 structure, demonstrating that the 0.7 structure is not a transmission effect through a ballistic channel at zero in-plane magnetic field.