Electrical spin injection into semiconductors paves the way for exploring new phenomena in
the area of spin physics and new generations of spintronic devices. However the exact role
of interface states in the spin injection mechanism from a magnetic tunnel junction into a
semiconductor is still under debate. In this Letter, we demonstrate a clear transition from spin
accumulation into interface states to spin injection in the conduction band of n-Ge. We
observe spin signal amplification at low temperature due to spin accumulation into interface …

Spin injection into semiconductors is crucial for exploring spin physics and new spintronic
devices. Ge is of great interest for high carrier mobilities, long spin diffusion length and large
spin-orbit coupling to perform electric field spin manipulation. However the exact role of
interface states in spin injection mechanism in n-Ge has not been clarified yet. Here we
show a clear transition from spin accumulation into interface states to spin injection in the Ge
conduction band. For this purpose, we have grown CoFeB/MgO as a spin injector on …