Reversal of Spin Polarization in Fe/GaAs (001) Driven by Resonant Surface States: First-principles Calculations

Authors

Athanasios N. Chantis, Los Alamos National LaboratoryFollow
Kirill D. Belashchenko, University of Nebraska-LincolnFollow
D. L. Smith, Los Alamos National Laboratory, Los Alamos, New Mexico
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
Mark van Schilfgaarde, Arizona State UniversityFollow
R. C. Albers, Los Alamos National Laboratory, Los Alamos, New Mexico

ORCID IDs

Tsymbal http://orcid.org/0000-0002-6728-5485

Document Type

Article

Date of this Version

11-2007

Citation

Physical Review Letters(2007) 99: 196603

doi: 10.1103/PhysRevLett.99.196603

Comments

Copyright © 2007, American Physical Society. Used by permission

Abstract

A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to reverse the spin polarization with the voltage bias of electrons transmitted across this interface. Using a Green's function approach within the local spin-density approximation, we calculate the spin-dependent current in a Fe/GaAs/Cu tunnel junction as a function of the 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.