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Real space first-principles derived semiempirical pseudopotentials applied to tunneling magnetoresistance
In this letter we present a real space density functional theory (DFT)
localized basis set semi-empirical pseudopotential (SEP) approach. The method
is applied to iron and magnesium oxide, where bulk SEP and local spin density
approximation (LSDA) band structure calculations are shown to agree within
approximately 0.1 eV. Subsequently we investigate the qualitative
transferability of bulk derived SEPs to Fe/MgO/Fe tunnel junctions. We find
that the SEP method is particularly well suited to address the tight binding
transferability problem because the transferability error at the interface can
be characterized not only in orbital space (via the interface local density of
states) but also in real space (via the system potential). To achieve a
quantitative parameterization, we introduce the notion of ghost semi-empirical
pseudopotentials extracted from the first-principles calculated Fe/MgO bonding
interface. Such interface corrections are shown to be particularly necessary
for barrier widths in the range of 1 nm, where interface states on opposite
sides of the barrier couple effectively and play a important role in the
transmission characteristics. In general the results underscore the need for
separate tight binding interface and bulk parameter sets when modeling
conduction through thin heterojunctions on the nanoscale.Comment: Submitted to Journal of Applied Physic
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report
This Report summarizes the proceedings of the 2015 Les Houches workshop on
Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant
for high precision Standard Model calculations, (II) the new PDF4LHC parton
distributions, (III) issues in the theoretical description of the production of
Standard Model Higgs bosons and how to relate experimental measurements, (IV) a
host of phenomenological studies essential for comparing LHC data from Run I
with theoretical predictions and projections for future measurements in Run II,
and (V) new developments in Monte Carlo event generators.Comment: Proceedings of the Standard Model Working Group of the 2015 Les
Houches Workshop, Physics at TeV Colliders, Les Houches 1-19 June 2015. 227
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