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

• Published in: Physica. E, Low-dimensional systems & nanostructures Low-dimensional systems & nanostructures, 2011-06, Vol.43 (8), p.1518-1521
• Main Authors: Xia, Cai-Juan, Liu, De-Sheng, Liu, Han-Chen, Zhai, Xue-Jun
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; Methods of electronic structure calculations; Molecular electronics, nanoelectronics; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2011.04.020

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. [Display omitted] ► 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.