Electrical spin injection into Si(001) through a SiO2 tunnel barrier

TL;DR

This paper demonstrates spin-polarized electron injection from Fe into silicon through a SiO2 tunnel barrier, confirming Fe's majority spin influence and achieving at least 30% electron spin polarization at low temperature.

Contribution

It presents the first demonstration of electrical spin injection into silicon via a SiO2 tunnel barrier, with detailed analysis confirming spin polarization transfer from Fe.

Findings

Spin-polarized tunneling from Fe into Si observed

Electroluminescence polarization tracks Fe magnetization

Electron spin polarization in Si is at least 30% at 5 K

Abstract

We demonstrate spin polarized tunneling from Fe through a SiO2 tunnel barrier into a Si n-i-p heterostructure. Transport measurements indicate that single step tunneling is the dominant transport mechanism. The circular polarization, Pcirc, of the electroluminescence (EL) shows that the tunneling spin polarization reflects Fe majority spin. Pcirc tracks the Fe magnetization, confirming that the spin-polarized electrons radiatively recombining in the Si originate from the Fe. A rate equation analysis provides a lower bound of 30% for the electron spin polarization in the Si at 5 K.