Spin-injection through an Fe/InAs Interface

TL;DR

This paper calculates the spin-dependent interface resistance between Fe and InAs, showing that high-quality epitaxial interfaces are essential for efficient spin injection due to symmetry effects and disorder impacts.

Contribution

It provides first-principles calculations of spin-dependent interface resistance, highlighting the importance of interface quality for spin injection efficiency.

Findings

Specular Fe/InAs interface acts as an efficient spin filter with high polarization.

Disorder reduces spin asymmetry significantly.

Specular interface resistance comparable to a few microns of bulk InAs.

Abstract

The spin-dependence of the interface resistance between ferromagnetic Fe and InAs is calculated from first-principles for specular and disordered (001) interfaces. Because of the symmetry mismatch in the minority-spin channel, the specular interface acts as an efficient spin filter with a transmitted current polarisation between 98 an 89%. The resistance of a specular interface in the diffusive regime is comparable to the resistance of a few microns of bulk InAs. Symmetry-breaking arising from interface disorder reduces the spin asymmetry substantially and we conclude that efficient spin injection from Fe into InAs can only be realized using high quality epitaxial interfaces.