Effect of interface bonding on spin-dependent tunneling from the oxidized Co surface

Authors

Kirill D. Belashchenko, University of Nebraska-LincolnFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
Mark van Schilfgaarde, Arizona State UniversityFollow
Derek A. Stewart, Sandia National Laboratories, Livermore, CaliforniaFollow
Ivan I. Oleynik, University of South FloridaFollow
Sitaram Jaswal, University of NebraskaFollow

Date of this Version

5-7-2004

Comments

Published in Physical Review B, 69, 174408 (7 May 2004)
Copyright © 2004 The American Physical Society. Used by permission
URL: http://link.aps.org/abstract/PRB/v69/e174408
doi:10.1103/PhysRevB.69.174408

Abstract

We demonstrate that the factorization of the tunneling transmission into the product of two surface transmission functions and a vacuum decay factor allows one to generalize Jullière's formula and explain the meaning of the "tunneling density of states" in some limiting cases. Using this factorization we calculate spin-dependent tunneling from clean and oxidized fcc Co surfaces through vacuum into Al using the principal-layer Green's-function approach. We demonstrate that a monolayer of oxygen on the Co(111) surface creates a spin-filter effect due to the Co-O bonding which produces an additional tunneling barrier in the minority-spin channel. This changes the minority-spin dominated conductance for the clean Co surface into a majority-spin dominated conductance for the oxidized Co surface.