Self-consistent conductance calculations on molecular calipers using a transfer matrix method

A rapid method of conductance calculation using an iterative transfer matrix algorithm has been developed. Its use is demonstrated with a simple metal-molecule-metal system. By using a DFT Hamiltonian and charge self-consistency, we avoid any dependence on fitting. Here we solve a self-consistent potential, which obviates the need to parametrize the voltage. Moreover, in examining an experimental set-up developed at Arizona State University, the molecular conductance across a variety of gap lengths can be calculated and compared to experiment, and the implementation of a proposed nano-caliper device can be evaluated. Conduction across the molecule occurs in multiple channels; gold states couple with varying strengths to the HOMO of the molecule. We will report the effects of strain across the molecule, and of distortion of the molecule, on the conductive nature of the coupling.