Stochastic modulation in molecular electronic transport junctions: Molecular dynamics coupled with charge transport calculations

The experimental variation in conductance that can be expected through dynamically evolving Au-molecule-Au junctions is approximated using molecular dynamics to model thermal fluctuations and a nonequilibrium Green's function code (Huckel-IV 2.0) to calculate the charge transport. This generates a statistical set of conductance data that can be used to compare directly with experimental results. Experimental measurements on Au-single molecule junctions show a large variation in conductance values between different identically prepared junctions. Our computational results indicate that the Au-Au and the Au-molecule fluctuations provide extensive geometric freedom and an associated broad distribution in calculated conductance values. Our results show agreement with experimental measurements of the low bias voltage conductance and conductance distribution for both thiol-Au and amine-Au linker structures.