Tuning thermal transport in graphene via combinations of molecular antiresonances

TL;DR

This paper introduces a method to control phonon thermal transport in low-dimensional systems by using molecular adsorbates to create antiresonances, enabling tailored thermal resistance for thermoelectric and thermal management applications.

Contribution

It demonstrates how molecular antiresonances can be engineered to manipulate thermal transport properties, revealing non-additive resistance effects and spectrum-dependent behavior.

Findings

Thermal resistance due to individual molecules is nearly constant across species.

Combinations of different molecular species show non-additive resistance effects.

Anti-resonance positions critically influence the net thermal resistance.

Abstract

We propose a method to engineer the phonon thermal transport properties of low dimensional systems. The method relies on introducing a predetermined combination of molecular adsorbates, which give rise to antiresonances at frequencies specific to the molecular species. Despite their dissimilar transmission spectra, thermal resistances due to individual molecules remain almost the same for all species. On the other hand, thermal resistance due to combinations of different species are not additive and show large differences depending on the species. Using a toy model, the physics underlying the violation of resistance summation rule is investigated. It is demonstrated that equivalent resistance of two scatterers having the same resistances can be close to the sum of the constituents or $\sim$70\% of it depending on the relative positions of the antiresonances. The relative positions of the antiresonances determine the net change in transmission, therefore the equivalent resistance. Since the entire spectrum is involved in phonon spectrum changes in different parts of the spectrum become important. Performing extensive first-principles based computations, we show that these distinctive attributes of phonon transport can be useful to tailor the thermal transport through low dimensional materials, especially for thermoelectric and thermal management applications.