Magnetoconductance Anisotropies and Aharonov-Casher Phases

TL;DR

This paper proposes a method to measure the geometric Aharonov-Casher phase via magnetoconductance anisotropy, enabling precise calibration of spin-orbit coupling strength in spintronic devices.

Contribution

It introduces a novel approach to determine spin-orbit coupling strength by analyzing magnetoconductance anisotropy, bypassing interference-based measurements.

Findings

Magnetoconductance anisotropy reflects the geometric phase.

Method applicable to various spin-orbit interactions.

Enables external electric field tuning of spin-orbit coupling.

Abstract

The spin-orbit interaction is a key tool for manipulating and functionalizing spin-dependent electron transport. However, the precise value of the spin-orbit coupling constant is hard to determine and control. Here we propose a measurement of the geometric (Aharonov-Casher) phase of the electron wavefunction generated by the spin-orbit coupling as a means to deduce the spin-orbit coupling strength in weak links. Unlike other proposed measurements of geometric phases, which rely on interference, we show that the anisotropy of the magnetoconductance, measured at different directions of an external magnetic field,is determined by the geometric phase. Specifically we consider weak links in which the Rashba interaction is caused by an external electric field, but our method is expected to apply also for other forms of the spin-orbit coupling. Measuring this magnetoconductance anisotropy thus allows calibrating Rashba spintronic devices by an external electric field that tunes the spin-orbit interaction.