Estimation of phonon relaxation time for silicon by means of using the velocity autocorrelation function of atoms in molecular dynamics

Results of the ab initio molecular dynamics calculations of silicon crystals are presented by means of analysis of the velocity autocorrelation function and determination of mean phonon relaxation time. The mean phonon relaxation time is crucial for prediction of the phonon-associated coefficient of...

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Bibliographic Details
Published in:Bulletin of the Polish Academy of Sciences. Technical sciences 2019-01, Vol.67 (3), p.651-656
Main Authors: Andriyevsky, B., Maliński, M., Buryło, Ł., Stadnyk, V.Y., Romanyuk, M.O., Piekarski, J., Andriyevska, L.
Format: Article
Language:English
Subjects:
Autocorrelation functions
coefficient of thermal diffusivity
Coefficients
Diffusivity
Heat conductivity
Heat transfer
Kinetic energy
Mathematical analysis
Molecular dynamics
Phonons
Relaxation time
relaxation time of the velocity autocorrelation function
Semiconductors
Silicon
Thermal conductivity
Thermal diffusivity
Velocity
Wide bandgap semiconductors
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Summary:Results of the ab initio molecular dynamics calculations of silicon crystals are presented by means of analysis of the velocity autocorrelation function and determination of mean phonon relaxation time. The mean phonon relaxation time is crucial for prediction of the phonon-associated coefficient of thermal conductivity of materials. A clear correlation between the velocity autocorrelation function relaxation time and the coefficient of thermal diffusivity has been found. The analysis of the results obtained has indicated a decrease of the velocity autocorrelation function relaxation time t with increase of temperature. The method proposed may be used to estimate the coefficient of ther-mal diffusivity and thermal conductivity of the materials based on silicon and of other wide-bandgap semiconductors. The correlation between kinetic energy fluctuations and relaxation time of the velocity autocorrelation function has been calculated with the relatively high coefficient of determination R2 = 0.9396. The correlation obtained and the corresponding approach substantiate the use of kinetic energy fluctuations for the calculation of values related to heat conductivity in silicon-based semiconductors (coefficients of thermal conductivity and diffusivity).
ISSN:2300-1917
0239-7528
2300-1917
DOI:10.24425/bpasts.2019.129663