Simulation and Analysis of BDT Molecule with Au Electrodes as a Molecular Switch

Molecular electronics has the potential to miniaturize devices to atomic and molecular scales. This is significant given that CMOS devices are reaching fundamental limitations. The molecular orbital energies have been previously computed for a number of Benzene derivatives. The current flow in 1,4-Benzene Dithiol with Au electrodes has been analyzed using Hamiltonian and self-energies. The single molecule conductance has been experimentally measured using a mechanically break junction technique. The top-hollow and top-top geometry models have been proposed for alkanedithiols. Here, the 1,4-Benzene Dithiol with Au electrodes has been simulated using Density Function Theory. It is seen that the choice of bases functions, bond length and angles is critical for simulation convergence. From the simulation, the molecular orbital energies, potential energy, Band gap energy and Ionization Potential are determined. It is seen that the molecule without Au electrodes has a high band gap energy of 5.5576 eV implying an electrical insulator behavior. This molecule's top-top and top-hollow geometries (with Au electrodes) simulations indicate a slightly higher conductivity and better stability for top-hollow geometry (ON state). These simulations are broadly consistent with the earlier experimental results.