Negative differential resistance in polyoxometalates

Large-scale (with peak-to-valley ratios up to 100) controllable multiple negative differential resistances have been revealed in tunneling spectra of one of the polyoxometalates (ammonium decamolybdodicobaltate(III)) in experiments with a scanning tunneling microscope in air under normal conditions and standard humidity. Conditions necessary for the observation of such negative differential resistances have been determined. A mechanism of their formation common for all nanostructures with weak intramolecular bonds has been revealed. A strategy for the selection of materials for molecular electronics based on the optimization of the composition and architecture of metal oxides has been proposed.