Electric Field Modulation of Spin Transport

TL;DR

This paper demonstrates that modest electric fields can effectively modulate spin transport at room temperature in germanium, enabling potential spintronic device applications without cryogenic cooling.

Contribution

It introduces a novel scheme where electric fields control spin transport at room temperature, exploiting finite spin lifetime rather than mitigating it.

Findings

Electric field of 24 V/cm modulates spin transport by an order of magnitude.

Electric fields can guide spins over macroscopic distances at room temperature.

Spin accumulation can be rapidly modulated using electric fields in germanium.

Abstract

The finite spin lifetime in solids is often considered a major hindrance for the development of spintronic devices, which typically require cryogenic temperatures to mitigate this phenomenon. In this work we show that this feature can instead be exploited to realize a scheme where spin transport is modulated at room temperature by a modest electric field. A field directed antiparallel (parallel) to the spin-diffusion velocity can in fact largely increase (decrease) the spin-transport length compared with the zero field case. We find that applying an electric field E = 24 V/cm along a 40 mm-long path in germanium results in about one order of magnitude modulation of the spin-polarized electrons entering in the detector. The present work demonstrates that electric fields can be exploited for guiding spins over macroscopic distances and for realizing fast, room temperature modulation of spin accumulation.