When "small" terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

Gemma C. Solomon, Justin P. Bergfield, Charles A Stafford, Mark A. Ratner

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Quantum interference effects offer opportunities to tune the electronic and thermoelectric response of a quantum-scale device over orders of magnitude. Here we focus on single-molecule devices, in which interference features may be strongly affected by both chemical and electronic modifications to the system. Although not always desirable, such a susceptibility offers insight into the importance of "small" terms, such as through-space coupling and many-body charge-charge correlations. Here we investigate the effect of these small terms using different Hamiltonian models with Hückel, gDFTB and many-body theory to calculate the transport through several single-molecule junctions, finding that terms that are generally thought to only slightly perturb the transport instead produce significant qualitative changes in the transport properties. In particular, we show that coupling of multiple interference features in cross-conjugated molecules by through-space coupling will lead to splitting of the features, as can correlation effects. The degeneracy of multiple interference features in cross-conjugated molecules appears to be significantly more sensitive to perturbations than those observed in equivalent cyclic systems and this needs to be considered if such supernodes are required for molecular thermoelectric devices.

Original languageEnglish (US)
Pages (from-to)862-871
Number of pages10
JournalBeilstein Journal of Nanotechnology
Volume2
Issue number1
DOIs
Publication statusPublished - 2011

    Fingerprint

Keywords

  • GDFTB
  • Huckel model
  • Many-body effects
  • Molecular electronics
  • Quantum interference
  • Thermoelectrics
  • Topology

ASJC Scopus subject areas

  • Materials Science(all)
  • Electrical and Electronic Engineering
  • Physics and Astronomy(all)

Cite this