arXiv subjects

Vasyl Kuryliuk

Publications and source records attributed to Vasyl Kuryliuk.

3 recordsLinked to original sources

arXiv2024

Features of phonon scattering by a spherical pore: molecular dynamics insight

There is still a gap in understanding phonons scattering by geometrical defects at the nanoscale, and it remains a significant challenge for heat transfer management in nanoscale devices and systems. In this study, we aim to explore the characteristics of phonon scattering by a single pore to gain insights into thermal transport in nanostructures. The paper outlines a methodology for assessing the spatial distribution of the magnitude of the radial, azimuthal, and polar components of the velocity of scattered phonons by a spherical pore. We demonstrated that the size parameter, commonly employed in electromagnetic wave scattering theory, is vital in determining the scattering regime. Specifically, we show that calculated scattering efficiency has the same pattern as one commonly obtained in classical wave scattering theory. However, we found that crystallographic directions are pivotal in shaping the scattering patterns, especially in the regions where scattering patterns are defined by the Mie resonances. This observation holds significance in understanding the influence of phonon coherence on thermal transport in nanostructured materials.

cond-mat.mes-hall↗

arXiv2023

Thermal Transport Properties of Nanoporous Silicon with Significant Specific Surface Area

This paper studies thermal transport in nanoporous silicon with a significant specific surface area. First, the equilibrium molecular dynamics approach was used to obtain the dependence of thermal conductivity on a specific surface area. Then, a modified phonon transport kinetic theory-based approach was developed to analyze thermal conductivity. Two models were used to evaluate the phonon mean free path in the porous materials. The first model approximates the dependence of the mean free path only with the specific surface area, and the second one investigates the dependence of the mean free path variation with the porosity in the peculiar case of a highly porous matrix. Both models approximate molecular dynamics data well for the smaller porosity values, while the first model fails for large porosities. The second model matches well with molecular dynamics simulations for all considered ranges of the porosities. This work illustrates that the phonon mean free path dependence with the porosity/volume fraction of composite materials is essential for describing thermal transport in systems with significant surface-to-volume fractions.

cond-mat.mes-hall↗

arXiv2019

Thermal conductivity of strained silicon: molecular dynamics insight and kinetic theory approach

In this work, we investigated tensile and compression forces effect on the thermal conductivity of silicon. We used equilibrium molecular dynamics approach for the evaluation of thermal conductivity considering different interatomic potentials. More specifically, we tested Stillinger-Weber, Tersoff, Environment-Dependent Interatomic Potential and Modified Embedded Atom Method potentials for the description of silicon atom motion under different strain and temperature conditions. Additionally, we extracted phonon density of states and dispersion curves from molecular dynamics simulations. These data were used for direct calculations of thermal conductivity considering the kinetic theory approach. Comparison of molecular dynamics and kinetic theory simulations results as a function of strain and temperature allowed us to investigate the different factors affecting the thermal conductivity of strained silicon.

cond-mat.mtrl-sci↗