Achievement

Physics trainee David Strubbe has calculated the conductance of a set of organic molecules in nanoscale molecular junctions and demonstrated quantitative agreement with STM break-junction experiments. Studies of electronic transport in these systems gives fundamental insight into conductance at the nanoscale, and may lead to future molecular electronic devices. However, standard methods based on density-functional theory overestimate the conductance. In collaboration with researchers at the Molecular Foundry, we have developed a new method for these calculations that corrects the energy levels of the junction and shown its success for a range of organic molecules: benzenediamines, butanediamines, and bipyridines. He has also come up with an improved way of determining which molecular orbital is responsible for conductance, by removing an exponential decay from the scattering wavefunction and then projecting it onto the HOMO, LUMO, etc.