First-principles investigation of electronic coupling effects between organic molecules and transition metal electrodes on conduction

We investigate electronic transport in long chain molecules sandwiched between metallic electrodes. The calculations are carried out using the non-equilibrium Green function method and a basis set of localized orbitals, which are optimized to minimize the DFT total energy of the system. The optimization is performed on a grid, using multigrid techniques~~to accelerate convergence. Our model systems consist of saturated hydrocarbon (alkane) chains having thiol (-SH) and amino (-NO$_2$) end groups attached to transition metal electrodes. We show that the current-voltage characteristics strongly depend on the coupling between the molecule and the metal electrodes.