Image-charge induced localization of molecular orbitals at metal-molecule interfaces: Self-consistent GW calculations

Abstract

Quasiparticle (QP) wave functions, also known as Dyson orbitals, extend the concept of single-particle states to interacting electron systems. Here we employ many-body perturbation theory in the GW approximation to calculate the QP wave functions for a semi-empirical model describing a $\pi$-conjugated molecular wire in contact with a metal surface. We find that image charge effects pull the frontier molecular orbitals toward the metal surface while orbitals with higher or lower energy are pushed away. This affects both the size of the energetic image charge shifts and the coupling of the individual orbitals to the metal substrate. Full diagonalization of the QP equation and, to some extent, self-consistency in the GW self-energy, is important to describe the effect which is not captured by standard density functional theory or Hartree-Fock. These results should be important for the understanding and theoretical modeling of electron transport across metal-molecule interfaces.

7 pages, 6 figures

References in corpus (6)

• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• First-principles GW calculations for fullerenes, porphyrins, phtalocyanine, and other molecules of interest for organic photovoltaic applications
• Renormalization of Molecular Quasiparticle Levels at Metal-Molecule Interfaces: Trends Across Binding Regimes
• Electronic energy level alignment at metal-molecule interfaces with a GW approach
• Ab initio complex band structure of conjugated polymers: Effects of hydrid DFT and GW schemes
• Screening effects in a density functional theory based description of molecular junctions in the Coulomb blockade regime

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• Density functional descriptions of interfacial electronic structure
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