Reversal of spin polarization in Fe/GaAs (001) driven by resonant surface states: First-principles calculations

Chantis, Athanasios N.; Belashchenko, Kirill D.; Smith, Darryl L.; Tsymbal, Evgeny Y.; van Schilfgaarde, Mark; Albers, Robert C.

Reversal of spin polarization in Fe/GaAs (001) driven by resonant surface states: First-principles calculations

Authors

Chantis, Athanasios N.

Belashchenko, Kirill D.

Smith, Darryl L.

Tsymbal, Evgeny Y.

van Schilfgaarde, Mark

Albers, Robert C.

Description

A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to reverse the spin polarization with voltage bias of electrons transmitted across this interface. Using a Green's function approach within the local spin density approximation we calculate spin-dependent current in a Fe/GaAs/Cu tunnel junction as a function of applied bias voltage. We find a change in sign of the spin polarization of tunneling electrons with bias voltage due to the interface minority-spin resonance. This result explains recent experimental data on spin injection in Fe/GaAs contacts and on tunneling magnetoresistance in Fe/GaAs/Fe magnetic tunnel junctions.