Electrochemical control of quantum interference in anthraquinonebased molecular switches
Abstract
Using firstprinciples calculations we analyze the electronic transport properties of a recently proposed anthraquinonebased electrochemical switch. Robust conductance on/off ratios of several orders of magnitude are observed due to destructive quantum interference present in the anthraquinone but absent in the hydroquinone molecular bridge. A simple explanation of the interference effect is achieved by transforming the frontier molecular orbitals into localized molecular orbitals thereby obtaining a minimal tightbinding model describing the transport in the relevant energy range in terms of hopping via the localized orbitals. The topology of the tightbinding model, which is dictated by the symmetries of the molecular orbitals, determines the amount of quantum interference.
 Publication:

Journal of Chemical Physics
 Pub Date:
 June 2010
 DOI:
 10.1063/1.3451265
 arXiv:
 arXiv:1005.0529
 Bibcode:
 2010JChPh.132v4104M
 Keywords:

 density functional theory;
 electrical conductivity;
 electrochemistry;
 molecular electronics;
 orbital calculations;
 organic compounds;
 quantum interference phenomena;
 tightbinding calculations;
 85.65.+h;
 73.61.Ph;
 73.23.b;
 71.15.Ap;
 71.15.Mb;
 82.45.Vp;
 Molecular electronic devices;
 Polymers;
 organic compounds;
 Electronic transport in mesoscopic systems;
 Basis sets and related methodology;
 Density functional theory local density approximation gradient and other corrections;
 Semiconductor materials in electrochemistry;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 6 pages, 6 figures