Heat dissipation and its relation to molecular orbital energies in single-molecule junctions

We present a theoretical study of the heat dissipation in single-molecule junctions. In order to investigate the heat dissipation in the electrodes and the relationship between the transmission spectra and the electronic structures, we consider a toy model in which electrodes are linked by a two-level molecular bridge. By using the Landauer approach, we show how heat dissipation in the electrodes of a molecular junction is related to its transmission characteristics. We show that in general, heat is not equally dissipated in the left and right electrodes of the junction and it depends on the bias polarity and the positions of the molecule's energy levels with respect to the Fermi level. Also, we exploit the molecule as a junction and the results show a good agreement with the toy model. Our results for the heat dissipation are remarkable in the sense that they can be used to detect which energy levels of a junction are dominated in the transport process.