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 at LincolnFollow
Mark van Schilfgaarde, Arizona State UniversityFollow
R. C. Albers, Los Alamos National Laboratory, Los Alamos, New Mexico

Date of this Version

11-2007

Comments

Published in Physical Review Letters 99, 196603 (2007); DOI: 10.1103/PhysRevLett.99.196603; Copyright © 2007 The American Physical Society. Used by permission. http://link.aps.org/abstract/PRL/v99/e196603

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.