Electrical spin injection and detection in an InAs quantum well

TL;DR

This paper reports the successful electrical detection of spin injection and diffusion in InAs quantum wells, with potential applications in spintronic devices like spin transistors.

Contribution

It demonstrates fully electrical detection of spin injection in InAs quantum wells and measures spin diffusion length and polarization at various temperatures.

Findings

Spin diffusion length of 1.8 μm at 20 K

Injected spin polarization of 1.9% at 20 K

Polarization remains at 1.4% at room temperature

Abstract

We demonstrate fully electrical detection of spin injection in InAs quantum wells. A spin polarized current is injected from a NiFe thin film to a two-dimensional electron gas (2DEG) made of InAs based epitaxial multi-layers. Injected spins accumulate and diffuse out in the 2DEG, and the spins are electrically detected by a neighboring NiFe electrode. The observed spin diffusion length is 1.8 um at 20 K. The injected spin polarization across the NiFe/InAs interface is 1.9% at 20 K and remains at 1.4% even at room temperature. Our experimental results will contribute significantly to the realization of a practical spin field effect transistor.