Phonon wave-packet technique

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Table of contents

Abstract
Résumé
1 Introduction
1.1 Phonon as a wave
1.2 Phonon interference in thermal transport
1.3 Basics of phonons
1.3.1 One-dimensional open system of coupled masses
1.3.2 Periodic Boundary Condition
1.3.3 Normal modes and phonon energy
1.4 Organization of the Thesis
2 Atomistic Simulation of Phonon Transport
2.1 Classical molecular dynamics
2.1.1 Generality
2.1.2 Limitation
2.2 Phonon transmission coefficient
2.2.1 Phonon wave-packet technique
2.2.2 Green’s function and phonon Green’s Function
2.3 Interface thermal conductance
2.3.1 Landauer’s formalism
2.3.2 Molecular dynamics
2.4 Lattice thermal conductivity
2.4.1 Phonon group velocity
2.4.2 Phonon relaxation time
2.4.3 Thermal conductivity from Green-Kubo formulation .
2.5 Conclusions
3 Phonon Interference and Energy Transport in Nonlinear Lattices with Resonance Defects
3.1 Introduction
3.2 Atomistic model and Methodology
3.2.1 Model Structure
3.2.2 Methodology
3.3 Results and Discussions
3.3.1 Interference Resonance Profile
3.3.2 Isotopic Shift of Resonances
3.3.3 Phonon Screening Effect
3.3.4 Two-Path Phonon Interference in Si crystal with Ge impurities
3.3.5 Random Distribution of Atoms
3.3.6 Nonlinear Effects
3.3.7 Wave Packet Coherence Length Determination
3.4 Conclusions
4 Ultra-compact Interference Phonon Nanocapacitor for Storage and Lasing of Terahertz Lattice Waves
4.1 Introduction
4.2 Atomistic Model
4.3 Results and Discussions
4.3.1 Linewidth narrowing by adiabatic cooling
4.3.2 Phonon reflection on the mirror
4.3.3 Phonon localization
4.3.4 Controllabe phonon emission
4.4 Conclusions
5 Harmonic Phonon Interferences Reduce Heat Conduction
5.1 Introduction
5.2 Atomistic Scheme
5.3 Results and Discussions
5.3.1 Harmonic force constants determination from density functional perturbation theory (DFPT) calculations
5.3.2 Phonon transmission
5.3.3 Alloy thermal conductivity
5.3.4 Phonon spectrum of of the diatomic 1D chain and the SiGe alloy
5.3.5 Anharmonic relaxation time
5.4 Conclusions
6 Conclusions and Perspectives
6.1 Conclusions
6.2 Perspectives
References