Large-scale negative differential resistances in electron tunneling transport through heteropoly compound molecules

摘要

In high-vacuum STM experiments at room temperature, the tunneling spectra are measured for molecules of phosphomolybdic acid (H_3PMo_(12)O_(40)), a "classic" example of heteropoly compounds that are promising as a basis for the creation of new elements of nanoelectronics. Examples of spectra containing multiple negative differential resistances (NDRs) with abnormally large (up to 10~2) peak-to-valley ratios have been discovered for the first time. The dependences of the discovered NDRs on the vacuum gap, the polarity of the applied voltage, and the magnitude and direction of the tunneling current are established. A new mechanism of formation of large-scale multiple NDRs in the nanostructures based on the Wannier-Stark quantum localization effect is presented.