The Importance of Fe Surface States For Magnetic Tunnel Junction Based Spintronic Devices

Authors

Athanasios N. Chantis, Los Alamos National LaboratoryFollow
Kirill D. Belashchenko, University of Nebraska-LincolnFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
Inna V. Sus, Los Alamos National Laboratory

Document Type

Article

Date of this Version

2008

Citation

Modern Physics Letters B, Vol. 22, No. 26 (2008) 2529–2551

Comments

Copyright 2008 World Scientific Publishing Company. Used by permission.

Abstract

In this article we give a review of our recent theoretical studies of the influence of Fe(001) surface (interface) states on spin-polarized electron transport across magnetic tunnel junctions with Fe electrodes. We show that minority-spin surface (interface) states are responsible for at least two effects which are important for spin electronics. First, they can produce a sizable tunneling anisotropic magnetoresistance in magnetic tunnel junctions with a single Fe electrode. The effect is driven by a Rashba shift of the resonant surface band when the magnetization changes direction. This can introduce a new class of spintronic devices, namely, tunneling magnetoresistance junctions with a single ferromagnetic electrode. Second, in Fe/GaAs(001) magnetic tunnel junctions minority-spin interface states produce a strong dependence of the tunneling current spin polarization on applied electrical bias. A dramatic sign reversal within a voltage range of just a few tenths of an eV is predicted. This explains the observed sign reversal of spin polarization in recent experiments of electrical spin injection in Fe/GaAs(001) and related reversal of tunneling magnetoresistance through vertical Fe/GaAs/Fe trilayers.