Transport in single-molecule transistors: Kondo physics and negative differential resistance

摘要

We report two examples of transport phenomena based on sharp features in theeffective density of states of molecular-scale transistors: Kondo physics inC$_{60}$-based devices, and gate-modulated negative differential resistance(NDR) in ``control'' devices that we ascribe to adsorbed contamination. Wediscuss the need for a statistical approach to device characterization, and thecriteria that must be satisfied to infer that transport is based on singlemolecules. We describe apparent Kondo physics in C$_{60}$-based single-moleculetransistors (SMTs), including signatures of molecular vibrations in the Kondoregime. Finally, we report gate-modulated NDR in devices made withoutintentional molecular components, and discuss possible origins of thisproperty.