Macroscopic transverse drift of long current-induced spin coherence in two-dimensional electron gases

TL;DR

This study visualizes long-range spin coherence transport in a two-dimensional electron gas, demonstrating nanosecond coherence times over half-millimeter distances due to material properties and spin-orbit effects.

Contribution

It provides the first direct imaging of macroscopic transverse spin transport in a 2D electron gas with detailed analysis of underlying material properties.

Findings

Spin coherence transported over 0.5 mm distance

Coherence times in the nanoseconds range

Large spin transport length explained by material properties

Abstract

We imaged the transport of current-induced spin coherence in a two-dimensional electron gas confined in a triple quantum well. Nonlocal Kerr rotation measurements, based on the optical resonant amplification of the electrically-induced polarization, revealed a large spatial variation of the electron g factor and the efficient generation of a current controlled spin-orbit field in a macroscopic Hall bar device. We observed coherence times in the nanoseconds range transported beyond half-millimeter distances in a direction transverse to the applied electric field. The measured long spin transport length can be explained by two material properties: large mean free path for charge diffusion in clean systems and enhanced spin-orbit coefficients in the triple well.