Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 40: Transport: Molecular Electronics and Photonics (jointly with CPP, HL, MA, O)

TT 40.12: Talk

Wednesday, March 22, 2017, 12:30–12:45, HSZ 201

Thermal conductance of Teflon and Polyethylene: Insight from an atomistic, single-molecule level — •Marius Buerkle and Yoshihiro Asai — AIST, Tsukuba, Japan

The thermal transport properties of teflon (polytetrafluoroethylene) and its polyethylene counterparts are, while highly desirable and widely used, only superficially understood. Here, we aim therefore to provide rigorous insight from an atomistic point of view in context of single-molecule devices. We show that for vinyl polymers adsorbed on metal-surfaces the thermal transport strongly depends one the properties of the metal-molecule interface and that the reduced thermal conductance observed for teflon derivatives originates in a reduced phonon injection life time. In asymmetric molecules phonon blocking on the intra molecular interface leads to a further reduction of thermal conductance. For hetrojunctions with different electrode materials we find that thermal conductance is suppressed due to a reduced overlap of the available phonon modes in the different electrodes. A detailed atomistic picture is thereby provided by studying the transport through perfluorooctane and octane on a single-molecule level using first principles transport calculations and nonequilibrium molecular dynamic simulations.