Experimental realization of a ballistic spin interferometer based on the Rashba effect using a nanolithographically defined square loop array

TL;DR

This paper demonstrates a gate-controlled electron spin interference in nanolithographically defined square loop arrays, showing significant spin precession controllability via the Rashba effect, advancing spintronic device development.

Contribution

It provides the first experimental realization of a ballistic spin interferometer based on the Rashba effect using nanolithographically defined square loop arrays.

Findings

Gate-controlled spin precession angle exceeds 0.75π

Large spin controllability achieved with gate voltage

Demonstrates potential for spin FET and qubit manipulation

Abstract

The gate-controlled electron spin interference was observed in nanolithographically defined square loop (SL) arrays fabricated using In$_{0.52}$Al$_{0.48}$As/In$_{0.53}$Ga$_{0.47}$As/In$_{0.52}$Al$_{0.48}$As quantum wells. In this experiment, we demonstrate electron spin precession in quasi-one-dimensional channels that is caused by the Rashba effect. It turned out that the spin precession angle $\theta$ was gate-controllable by more than 0.75$\pi$ for a sample with $L=1.5\mu$m, where $L$ is the side length of the SL. Large controllability of $\theta$ by the applied gate voltage as such is a necessary requirement for the realization of the spin FET device proposed by Datta and Das [Datta {\it et. al.}, Appl. Phys. Lett. {\bf 56}, 665 (1990)] as well as for the manipulation of spin qubits using the Rashba effect.