Quantum confinement theory of the heat capacity of thin films

Fuente: arXiv
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Main Author: Zaccone, Alessio
Format: Preprint
Published: 2024
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author Zaccone, Alessio
author_facet Zaccone, Alessio
contents A theory and mechanistic understanding of the thermal properties of solids under nanoscale confinement are currently missing. We develop a theoretical quantum confinement description of thin films which predicts a new physical law for the heat capacity. In particular, due to the suppression of vibrational modes caused by the thin film confinement, the vibrational density of states (VDOS) deviates from the Debye quadratic law in frequency and is, instead, cubic in frequency. This leads to a temperature dependence of the heat capacity which is $\sim T^4$ instead of Debye's $\sim T^3$ law. Furthermore, the new theory predicts a linear increase of the heat capacity upon increasing the nanometric film thickness. Both dependencies are found in excellent agreement with recent experimental data on NbTiN thin films.
format Preprint
id arxiv_https___arxiv_org_abs_2405_12600
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum confinement theory of the heat capacity of thin films
Zaccone, Alessio
Mesoscale and Nanoscale Physics
Materials Science
Soft Condensed Matter
Statistical Mechanics
Superconductivity
A theory and mechanistic understanding of the thermal properties of solids under nanoscale confinement are currently missing. We develop a theoretical quantum confinement description of thin films which predicts a new physical law for the heat capacity. In particular, due to the suppression of vibrational modes caused by the thin film confinement, the vibrational density of states (VDOS) deviates from the Debye quadratic law in frequency and is, instead, cubic in frequency. This leads to a temperature dependence of the heat capacity which is $\sim T^4$ instead of Debye's $\sim T^3$ law. Furthermore, the new theory predicts a linear increase of the heat capacity upon increasing the nanometric film thickness. Both dependencies are found in excellent agreement with recent experimental data on NbTiN thin films.
title Quantum confinement theory of the heat capacity of thin films
topic Mesoscale and Nanoscale Physics
Materials Science
Soft Condensed Matter
Statistical Mechanics
Superconductivity
url https://arxiv.org/abs/2405.12600