TY - JOUR
T1 - Enhancement of spin injection from ferromagnetic metal into a two-dimensional electron gas using a tunnel barrier
AU - Heersche, H. B.
AU - Schäpers, T.
AU - Nitta, J.
AU - Takayanagi, H.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001/10/15
Y1 - 2001/10/15
N2 - Using free electron approximation, we calculated the spin dependent tunnel conductance of ballistic ferromagnet / tunnel barrier / two-dimensional electron gas (FM/I/2DEG) junctions and FM/I/2DEG/I/FM double junctions for different barrier strengths. We find that a tunnel barrier improves spin injection considerably. For sufficiently strong barriers, it is predicted that the tunnel conductance ratio between spin up and spin down channels is, in first approximation, equal to the ratio between their Fermi velocities in the FM. For single junctions, this results in a significant current polarization (∼10%). This corresponds to a relative resistance change of several percent between parallel and antiparallel magnetization of the two FM electrodes, respectively, for the double junction. In the weak barrier regime, the magnitude and sign of the current polarization are strongly dependent on the (controllable) electron density in the 2DEG.
AB - Using free electron approximation, we calculated the spin dependent tunnel conductance of ballistic ferromagnet / tunnel barrier / two-dimensional electron gas (FM/I/2DEG) junctions and FM/I/2DEG/I/FM double junctions for different barrier strengths. We find that a tunnel barrier improves spin injection considerably. For sufficiently strong barriers, it is predicted that the tunnel conductance ratio between spin up and spin down channels is, in first approximation, equal to the ratio between their Fermi velocities in the FM. For single junctions, this results in a significant current polarization (∼10%). This corresponds to a relative resistance change of several percent between parallel and antiparallel magnetization of the two FM electrodes, respectively, for the double junction. In the weak barrier regime, the magnitude and sign of the current polarization are strongly dependent on the (controllable) electron density in the 2DEG.
UR - http://www.scopus.com/inward/record.url?scp=0001396365&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001396365&partnerID=8YFLogxK
U2 - 10.1103/physrevb.64.161307
DO - 10.1103/physrevb.64.161307
M3 - Article
AN - SCOPUS:0001396365
VL - 64
SP - 1613071
EP - 1613074
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 16
M1 - 161307
ER -