Large negative differential resistance in a molecular device with asymmetric contact geometries: A first-principles study

We report a first-principles study of electronic transport properties and negative differential resistance (NDR) in a single molecular device consisting of a pyrene-based molecule sandwiched between two gold electrodes with different contact geometries. The results show that the electronic transport properties are strongly dependent on the contact geometry. The transmission coefficients and spatial distributions of molecular orbitals under various external biases voltage are analyzed, and it suggests that the asymmetry of the coupling between the molecule and the electrodes with external bias leads to NDR.