Quasiparticle energies and lifetimes in a metallic chain model of a tunnel junction

Mark Szepieniec, Irene Yeriskin, J. C. Greer

Research output: Journal PublicationArticlepeer-review

11 Citations (Scopus)


As electronics devices scale to sub-10 nm lengths, the distinction between device and electrodes becomes blurred. Here, we study a simple model of a molecular tunnel junction, consisting of an atomic gold chain partitioned into left and right electrodes, and a central molecule. Using a complex absorbing potential, we are able to reproduce the single-particle energy levels of the device region including a description of the effects of the semi-infinite electrodes. We then use the method of configuration interaction to explore the effect of correlations on the systems quasiparticle peaks. We find that when excitations on the leads are excluded, the devices highest occupied molecular orbital and lowest unoccupied molecular orbital quasiparticle states when including correlation are bracketed by their respective values in the Hartree-Fock (Koopmans) and ΔSCF approximations. In contrast, when excitations on the leads are included, the bracketing property no longer holds, and both the positions and the lifetimes of the quasiparticle levels change considerably, indicating that the combined effect of coupling and correlation is to alter the quasiparticle spectrum significantly relative to an isolated molecule.

Original languageEnglish
Article number144105
JournalJournal of Chemical Physics
Issue number14
Publication statusPublished - 14 Apr 2013
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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