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@ARTICLE{Mavropoulos:531,
author = {Mavropoulos, Ph.},
title = {{S}pin injection from {F}e into {S}i(001): {A}b initio
calculations and role of the {S}i complex band structure},
journal = {Physical review / B},
volume = {78},
number = {5},
issn = {1098-0121},
address = {College Park, Md.},
publisher = {APS},
reportid = {PreJuSER-531},
pages = {054446},
year = {2008},
note = {Record converted from VDB: 12.11.2012},
abstract = {We study the possibility of spin injection from Fe into
Si(001), using the Schottky barrier at the Fe/Si contact as
tunneling barrier. Our calculations are based on
density-functional theory for the description of the
electronic structure and on a Landauer-Buttiker approach for
the current. The current-carrying states correspond to the
six conduction-band minima (pockets) of Si, which, when
projected on the (001) surface Brillouin zone (SBZ), form
five conductance hot spots: one at the SBZ center and four
symmetric satellites. The satellites yield a current
polarization of about $50\%,$ while the SBZ center can,
under very low gate voltage, yield up to almost $100\%,$
showing a zero-gate anomaly. This extremely high
polarization is traced back to the symmetry mismatch of the
minority-spin Fe wave functions to the conduction-band wave
functions of Si at the SBZ center. The tunneling current is
determined by the complex band structure of Si in the [001]
direction, which shows qualitative differences compared to
that of direct-gap semiconductors. Depending on the Fermi
level position and Schottky barrier thickness, the complex
band structure can cause the contribution of the satellites
to be orders of magnitude higher or lower than the central
contribution. Thus, by appropriate tuning of the interface
properties, there is a possibility to cut off the satellite
contribution and to reach high injection efficiency. Also,
we find that a moderate strain of $0.5\%$ along the [001]
direction is sufficient to lift the degeneracy of the
pockets so that only states at the zone center can carry
current.},
keywords = {J (WoSType)},
cin = {IAS-1 / IFF-1},
ddc = {530},
cid = {I:(DE-Juel1)IAS-1-20090406 / I:(DE-Juel1)VDB781},
pnm = {Kondensierte Materie},
pid = {G:(DE-Juel1)FUEK414},
shelfmark = {Physics, Condensed Matter},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000259368200102},
doi = {10.1103/PhysRevB.78.054446},
url = {https://juser.fz-juelich.de/record/531},
}