Local Atomic Heat Currents and Classical Interference in Single-Molecule Heat Conduction
Renai Chen, Inon Sharony, Abraham Nitzan
Abstract
We consider interference effects in vibrational heat conduction across single-molecule junctions. Previous theoretical descriptions of such effects have relied on the quantum Landauer-type expression for heat transport by harmonic molecules, and such observations are sometimes termed "quantum interference". Here we demonstrate via classical atomistic simulations of heat conduction in benzenedithiol single-molecule junctions that the room-temperature effect is essentially classical. In fact, classical simulations and quantum evaluation of room-temperature heat conduction in these systems yield similar results. Simulations of para-, meta-, and ortho-connected benzenedithiols between gold substrates yield conductions in the order para > ortho > meta, which is similar to trends found in the electronic conduction of these structures. The (essentially classical) interference origin of this ordering is indicated by the similarity of the quantum and classical behaviors of these systems.