Electrical spin injection and detection in Germanium using three terminal geometry

TL;DR

This paper demonstrates electrical spin injection and detection in n-type germanium-on-insulator using a three-terminal geometry, revealing spin signals up to 220 K and effects of interface roughness.

Contribution

It presents the first successful electrical spin injection and detection in germanium using a three-terminal setup with detailed analysis of interface effects.

Findings

Spin accumulation signal of ~1 meV observed.

Spin signals detectable up to 220 K.

Inverted Hanle effect indicates interface roughness influence.

Abstract

In this letter, we report on successful electrical spin injection and detection in \textit{n}-type germanium-on-insulator (GOI) using a Co/Py/Al$_{2}$O$_{3}$ spin injector and 3-terminal non-local measurements. We observe an enhanced spin accumulation signal of the order of 1 meV consistent with the sequential tunneling process via interface states in the vicinity of the Al$_{2}$O$_{3}$/Ge interface. This spin signal is further observable up to 220 K. Moreover, the presence of a strong \textit{inverted} Hanle effect points at the influence of random fields arising from interface roughness on the injected spins.