A quasi-classical mapping approach to vibrationally coupled electron transport in molecular junctions

Bin Li; Eli Y Wilner; Michael Thoss; Eran Rabani; William H Miller

doi:10.1063/1.4867789

A quasi-classical mapping approach to vibrationally coupled electron transport in molecular junctions

J Chem Phys. 2014 Mar 14;140(10):104110. doi: 10.1063/1.4867789.

Authors

Bin Li¹, Eli Y Wilner², Michael Thoss³, Eran Rabani⁴, William H Miller¹

Affiliations

¹ Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
² School of Physics and Astronomy, The Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
³ Institute for Theoretical Physics and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7/B2, 91058 Erlangen, Germany.
⁴ School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.

PMID: 24628155
DOI: 10.1063/1.4867789

Abstract

We develop a classical mapping approach suitable to describe vibrationally coupled charge transport in molecular junctions based on the Cartesian mapping for many-electron systems [B. Li and W. H. Miller, J. Chem. Phys. 137, 154107 (2012)]. To properly describe vibrational quantum effects in the transport characteristics, we introduce a simple transformation rewriting the Hamiltonian in terms of occupation numbers and use a binning function to facilitate quantization. The approach provides accurate results for the nonequilibrium Holstein model for a range of bias voltages, vibrational frequencies, and temperatures. It also captures the hallmarks of vibrational quantum effects apparent in step-like structure in the current-voltage characteristics at low temperatures as well as the phenomenon of Franck-Condon blockade.