Interference and Molecular Transport—A Dynamical View: Time-Dependent Analysis of Disubstituted Benzenes

Abstract

The primary issue in molecular electronics is measuring and understanding how electrons travel through a single molecule strung between two electrodes. A key area involves electronic interference that occurs when electrons can follow more than one pathway through the molecular entity. When the phases developed along parallel pathways are inequivalent, interference effects can substantially reduce overall conductance. This fundamentally interesting issue can be understood using classical rules of physical organic chemistry, and the subject has been examined broadly. However, there has been little dynamical study of such interference effects. Here, we use the simplest electronic structure model to examine the coherent time-dependent transport through meta- and para-linked benzene circuits, and the effects of decoherence. We find that the phase-caused coherence/decoherence behavior is established very quickly (femtoseconds), that the localized dephasing at any site reduces the destructive interference of the meta-linked species (raising the conductance), and that thermal effects are essentially ineffectual for removing coherence effects.

Controlling charge transport mechanisms in molecular junctions: Distilling thermally induced hopping from coherent-resonant conduction

“…More recently, it was applied to investigate e.g. electronic conduction in organic and biological molecular junctions [32][33][34][35][36][37] . Particularly, it was recently demonstrated in Refs.…”

Simulation of charge transport in organic semiconductors: A time-dependent multiscale method based on nonequilibrium Green's functions

“…To incorporate these fluctuations correctly, we employ a time-dependent (TD) transport approach based on nonequilibrium Green's function (NEGF) theory [9,10]. This method was previously applied to study charge transport through DNA [6,7,11,12], and it has recently been extended to account for charge relaxation and electric field effects [8]. Here, we apply the methodology in a different setting to study charge transport in significantly larger organic structures, in particular C 60 -based SAMs used in FETs [13,14] (cf.…”

Efficient auxiliary-mode approach for time-dependent nanoelectronics

“…Nevertheless, the computational time scales linearly with the number of time-steps. This method, along with its close variations (see, e.g., [23] for the general case and [24] for the wide-band limit), has already been successfully applied to study several realistic scenarios [25][26][27][28][29] and to model systems [30,31].…”