Thermoelectricity in tunneling nanostructures

Abstract

We employ a simple analytic model to calculate the thermopower of low-transparency molecular nanosystems. It turns out that the sign of the thermovoltage for this model depends sensitively on the participating molecular orbital, and one finds a sign change when the transport channel switches from the highest occupied molecular orbital to the lowest unoccupied molecular orbital. Comparing our results to recent experimental data obtained for a benzenedithiol molecule contacted with a scanning tunneling microscope tip, we observe good agreement.