Channel-based algebraic limits to conductive heat transfer

TL;DR

This paper develops new theoretical bounds on conductive heat transfer at the nanoscale, which are tighter than traditional limits and closely match actual transmission eigenvalues, aiding in the design of molecular junctions.

Contribution

It introduces novel bounds on heat conduction based on channel analysis that improve upon Landauer limits and are applicable to nanoscale systems.

Findings

New bounds are tighter than Landauer limits.

Bounds closely match actual transmission eigenvalues.

Applicable to phonon conduction in 1D chains.

Abstract

Recent experimental advances probing coherent phonon and electron transport in nanoscale devices at contact have motivated theoretical channel-based analyses of conduction based on the nonequilibrium Green's function formalism. The transmission through each channel has been known to be bounded above by unity, yet actual transmissions in typical systems often fall far below these limits. Building upon recently derived radiative heat transfer limits and a unified formalism characterizing heat transport for arbitrary bosonic systems in the linear regime, we propose new bounds on conductive heat transfer. In particular, we demonstrate that our limits are typically far tighter than the Landauer limits per channel and are close to actual transmission eigenvalues by examining a model of phonon conduction in a 1-dimensional chain. Our limits have ramifications for designing molecular junctions to optimize conduction.