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.

There is a large negative differential resistance (NDR) behavior can be found in the asymmetric system model A.Figure optionsDownload as PowerPoint slideHighlights
► The electronic transport properties are strongly dependent on the contact geometry.
► The NDR behavior can be observed over a certain range of applied bias voltage (1.2–2.0 V) in the asymmetric system.
► The asymmetric structure of both the molecule and the molecule–electrode couplings are responsible for the NDR behavior.