Active Tuning of Thermal Conductivity in Single layer Graphene Phononic crystals using Engineered Pore Geometry and Strain

Understanding thermal transport across length scales lays the foundation to developing high-performance electronic devices. Although many experiments and models of the past few decades have explored the physics of heat transfer at nanoscale, there are still open questions regarding the impact of periodic nanostructuring and coherent phonon effects, as well as the interaction of strain and thermal transport. Thermomechanical effects, as well as strains applied in flexible electronic devices, impact the thermal transport. In the simplest kinetic theory models, thermal conductivity is proportiona... Mehr ...

Verfasser: Radhakrishna Korlam
Dokumenttyp: Text
Erscheinungsdatum: 2021
Schlagwörter: Computational methods in fluid flow / heat and mass transfer (incl. computational fluid dynamics) / Mechanical engineering not elsewhere classified / Nanoscale characterisation / Phonon Transport / Thermal Conductivity / Nanoscale heat transfer / Strain / Nanopores / Non-Equilibrium Molecular Dynamics / Monte Carlo Methods / Callaway-Holland Model / Boltzmann Transport Equation / Mechanical Engineering / Heat and Mass Transfer Operations
Sprache: unknown
Permalink: https://search.fid-benelux.de/Record/base-29078769
Datenquelle: BASE; Originalkatalog
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Link(s) : https://doi.org/10.25394/pgs.17156000.v1

Understanding thermal transport across length scales lays the foundation to developing high-performance electronic devices. Although many experiments and models of the past few decades have explored the physics of heat transfer at nanoscale, there are still open questions regarding the impact of periodic nanostructuring and coherent phonon effects, as well as the interaction of strain and thermal transport. Thermomechanical effects, as well as strains applied in flexible electronic devices, impact the thermal transport. In the simplest kinetic theory models, thermal conductivity is proportional to the phonon group velocity, heat capacity, and scattering times. Periodic porous nanostructures impact the phonon dispersion relationship (group velocity) and the boundaries of the pores increase the scattering times. Strain, on the other hand, affects the crystal structure of the lattice and slightly increases the thermal conductivity of the material under compression. Intriguingly, applying strain combined with the periodic porous structures is expected to influence both the dispersion relation and scattering rates and yield the ability to tune thermal transport actively. But often these interrelated effects are simplified in models. This work evaluates the combination of structure and strain on thermal conductivity by revisiting some of the essential methods used to predict thermal transport for a single layer of graphene with a periodic porous lattice structure with and without applied strain. First, we use the highest fidelity method of Non-Equilibrium Molecular Dynamics (NEMD) simulations to estimate the thermal conductivity which considers the impact of the lattice structure, strain state, and phononic band structure together. Next, the impact of the geometry of the slots within the lattice is interrogated with Boltzmann Transport Equation (BTE) models under a Relaxation Time Approximation. A Monte Carlo based Boltzmann Transport Equation (BTE) solver is also used to estimate the thermal conductivity of phononic ...