Simultaneous measurement of electrical conductance and thermopower of single benzenedithiol molecular junctions

摘要

We have developed a system for the simultaneous measurement of electrical conductance and thermopower of the single benzenedithiol (BDT) molecular junction, which was characterized by inelastic electron tunneling spectroscopy, at low temperature. The simultaneous measurements revealed a negative correlation between the electrical conductance and the thermopower. Strong metal-molecule coupling at the single BDT molecular junction leads to high conductance and low thermopower because of the broadening of the conduction orbital, which explains the negative correlation. The observed fluctuation in conductance and thermopower reflects the change in the metal-molecule contact configuration and molecular orientation.