Flying electron spin control gates

TL;DR

This paper demonstrates a contactless, tunable gate for controlling moving electron spins using surface acoustic waves, enabling advanced on-chip spin manipulation and potential integration with photonic systems.

Contribution

It introduces a novel, contactless spin control method via SAW-induced strain, significantly enhancing precession control of flying spins compared to previous techniques.

Findings

Precession control exceeds previous results by an order of magnitude.

Strain-induced spin-orbit interaction explains the control mechanism.

Enables acoustically driven optical polarization modulation.

Abstract

The control of "flying" (or moving) spin qubits is an important functionality for the manipulation and exchange of quantum information between remote locations on a chip. Typically, gates based on electric or magnetic fields provide the necessary perturbation for their control either globally or at well-defined locations. Here, we demonstrate the dynamic control of moving electron spins via contactless gates that move together with the spin. The concept is realized using electron spins trapped and transported by moving potential dots defined by a surface acoustic wave (SAW). The SAW strain at the electron trapping site, which is set by the SAW amplitude, acts as a contactless, tunable gate that controls the precession frequency of the flying spins via the spin-orbit interaction. We show that the degree of precession control in moving dots exceeds previously reported results for unconstrained transport by an order of magnitude and is well accounted for by a theoretical model for the strain contribution to the spin-orbit interaction. This flying spin gate permits the realization of an acoustically driven optical polarization modulator based on electron spin transport, a key element for on-chip spin information processing with a photonic interface.