Evidence for the Presence of Spin Accumulation in Localized States at Ferromagnet-Silicon Interfaces

TL;DR

This paper provides experimental evidence of spin accumulation in localized states at ferromagnet-silicon interfaces, revealing temperature-dependent changes in spin signals and distinguishing between accumulation in the silicon channel and localized states.

Contribution

It demonstrates the detection of spin accumulation in localized states at ferromagnet-silicon interfaces using electrical Hanle effect measurements and analyzes temperature effects on the signals.

Findings

Spin accumulation detected in localized states at interfaces.

Temperature influences the spin-accumulation signals.

Different behaviors observed in silicon channel vs localized states.

Abstract

We experimentally show evidence for the presence of spin accumulation in localized states at ferromagnet-silicon interfaces, detected by electrical Hanle effect measurements in CoFe/$n^{+}$-Si/$n$-Si lateral devices. By controlling the measurement temperature, we can clearly observe marked changes in the spin-accumulation signals at low temperatures, at which the electron transport across the interface changes from the direct tunneling to the two-step one via the localized states. We discuss in detail the difference in the spin accumulation between in the Si channel and in the localized states.