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

ORAL

Abstract

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 [1,2] and on tunneling magnetoresistance in Fe/GaAs/Fe magnetic tunnel junctions [3]. \newline [1] S. A. Crooker {\it et al.}, Science {\bf 309}, 2191 (2005) \newline [2] X. Lou {\it et al.}, Nature Phys. 3, {\bf 197} (2007) \newline [3] J. Moser {\it et al.}, Appl. Phys. Lett. {\bf 89}, 162106 (2006)

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Authors

  • A.N. Chantis

    Theoretical Division, Los Alamos National Laboratory

  • K.D. Belashchenko

    University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska, USA, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • D.L. Smith

    Los Alamos National Laboratory, Theoretical Division, Los Alamos National Laboratory

  • E.Y. Tsymbal

    Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska, USA, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • Mark van Schilfgaarde

    Arizona State University, Arizona State Univesrity

  • R.C. Albers

    Theoretical Division, Los Alamos National Laboratory, Los Alamos National Laboratory