TY - JOUR
T1 - An approximate calculation for transport in magnetic tunnel junctions in the presence of localized states
AU - Levy, Peter M.
AU - Wang, Kuising
AU - Dederichs, Peter H.
AU - Heide, Carsten
AU - Zhang, Shufeng
AU - Szunyogh, Laszlo
N1 - Funding Information:
We would like to acknowledge and thank William Butler for sharing with us his unpublished results on the tunnelling conductance of Fe/vacuum/Fe junctions, Matthias Bode for bringing to our attention his spin-polarized tunnelling results, and Phivos Mavropolous, Nickos Papanikolaou, Andrei Ruckenstein and Christoph Uiberacker for helpful discussions. This work was supported by the Defense Advanced Research Projects Agency and Office of Naval Research (grant NOOO14-96-1-1207 and contracts MDA972-96-C-0014 and MDA972-99-C-0009), the National Science Foundation (grant INT-9602 192), NATO (grant CRG 960340), the Orszagos Tudomanyos Kutatasi Alapprogramok (grant OTKA T030240), and the TMR Network ERBFMXCT-960089.
PY - 2002/5
Y1 - 2002/5
N2 - In conventional calculations of transport in magnetic tunnel junctions, one usually assumes that the transverse momentum of the tunnelling electrons is conserved and that the itinerant electron states are orthogonal to localized states. However, in most of the junctions studied, there is diffuse scattering in both the bulk of the electrodes and the barrier so that the transverse momentum is not conserved, and there are processes that couple localized states at the electrode-barrier interface to the itinerant states in the bulk of the electrodes. While it is in principle possible to include these effects, it leads to lengthy calculations. Here we propose an approximate scheme in which we do not take explicit account of either of the effects mentioned above, but in which we calculate the tunnelling through all the states that exist at the electrode-barrier interfaces. We compare the k∥-resolved density of states and tunnelling currents across a junction in our approximate scheme with that found using the Landauer formalism in the ballistic limit.
AB - In conventional calculations of transport in magnetic tunnel junctions, one usually assumes that the transverse momentum of the tunnelling electrons is conserved and that the itinerant electron states are orthogonal to localized states. However, in most of the junctions studied, there is diffuse scattering in both the bulk of the electrodes and the barrier so that the transverse momentum is not conserved, and there are processes that couple localized states at the electrode-barrier interface to the itinerant states in the bulk of the electrodes. While it is in principle possible to include these effects, it leads to lengthy calculations. Here we propose an approximate scheme in which we do not take explicit account of either of the effects mentioned above, but in which we calculate the tunnelling through all the states that exist at the electrode-barrier interfaces. We compare the k∥-resolved density of states and tunnelling currents across a junction in our approximate scheme with that found using the Landauer formalism in the ballistic limit.
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U2 - 10.1080/13642810208224366
DO - 10.1080/13642810208224366
M3 - Article
AN - SCOPUS:0037053512
SN - 1364-2812
VL - 82
SP - 763
EP - 769
JO - Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties
JF - Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties
IS - 7
ER -