Thermal conduction and interface effects in nanoscale Fermi-Pasta-Ulam conductors

Abstract

We perform classical non-equilibrium molecular dynamics simulations to calculate heat flow through a microscopic junction connecting two larger reservoirs. In contrast to earlier works, we also include the reservoirs in the simulated region to study the effect of the bulk-nanostructure interfaces and the bulk conductance. The scalar Fermi--Pasta--Ulam (FPU) model is used to describe the effects of anharmonic interactions in a simple manner. The temperature profile close to the junction in the low temperature limit is shown to exhibit strong directional features that fade out when temperature increases. Simulating both the FPU chain and the two bulk regions is also shown to eliminate the non-monotous temperature variations found for simpler geometries and models. We show that with sufficiently large reservoirs, the temperature profile in the chain does not depend on the details of thermalization used at the boundaries.

9 pages, 7 figures, minor modifications to the previous version

References in corpus (8)

• Energy Dissipation and Transport in Nanoscale Devices
• Heat Transport in low-dimensional systems
• Heat transport in harmonic lattices
• Local Temperature and Universal Heat Conduction in FPU chains
• Heat conduction in a three dimensional anharmonic crystal
• Acoustic Phonon Tunneling and Heat Transport due to Evanescent Electric Fields
• Thermal conductance of the Fermi-Pasta-Ulam chains: Atomic to mesoscopic transition
• Thermal conduction in molecular chains: Non-Markovian effects

Cited by in corpus (8)

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• Phononic heat transport in the transient regime: An analytic solution
• Nonequilibrium phonon mean free paths in anharmonic chains
• Nonequilibrium processes from Generalised Langevin Equations: realistic nanoscale systems connected to two thermal baths
• Nonequilibrium Generalised Langevin Equation for the calculation of heat transport properties in model 1D atomic chains coupled to two 3D thermal baths
• Local heat current flow in ballistic phonon transport of graphene nanoribbons