Constrained-DFT method for accurate energy-level alignment of metal/molecule interfaces
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2013Access:
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A. M. Souza, I. Rungger, C. D. Pemmaraju, U. Schwingenschloegl and S. Sanvito, Constrained-DFT method for accurate energy-level alignment of metal/molecule interfaces, Physical Review B, 88, 16, 2013, 165112-Download Item:
Abstract:
We present a computational scheme for extracting the energy-level alignment of a metal/molecule interface,
based on constrained density functional theory and local exchange and correlation functionals. The method,
appliedheretobenzeneonLi(100),allowsustoevaluatecharge-transferenergies,aswellasthespatialdistribution
of the image charge induced on the metal surface. We systematically study the energies for charge transfer from
the molecule to the substrate as function of the molecule-substrate distance, and investigate the effects arising
from image-charge confinement and local charge neutrality violation. For benzene on Li(100) we find that the
image-charge plane is located at about 1.8
?
A above the Li surface, and that our calculated charge-transfer energies
compare perfectly with those obtained with a classical electrostatic model having the image plane located at the
same position. The methodology outlined here can be applied to study any metal/organic interface in the weak
coupling limit at the computational cost of a total energy calculation. Most importantly, as the scheme is based
on total energies and not on correcting the Kohn-Sham quasiparticle spectrum, accurate results can be obtained
with local/semilocal exchange and correlation functionals. This enables a systematic approach to convergence.
Author's Homepage:
http://people.tcd.ie/sanvitoshttp://people.tcd.ie/runggei
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Author: SANVITO, STEFANO; RUNGGER, IVAN
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Physical Review B88
16
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density functional theoryMetadata
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