Wave phase analysis for computing density of states, group velocity, and lateral shift in a 1D quasiperiodic structure containing layers of uniaxial medium and SiO2

2020 ◽  
Vol 59 (28) ◽  
pp. 8674
Author(s):  
Hadi Rahimi
Keyword(s):  
Group Velocity ◽  
Phase Analysis ◽  
Density Of States ◽  
Lateral Shift ◽  
Wave Phase ◽  
Quasiperiodic Structure

scholarly journals Heat transport through propagon-phonon interaction in epitaxial amorphous-crystalline multilayers

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Takafumi Ishibe ◽  
Ryo Okuhata ◽  
Tatsuya Kaneko ◽  
Masato Yoshiya ◽  
Seisuke Nakashima ◽  
...  
Keyword(s):  
Group Velocity ◽  
Density Of States ◽  
Heat Dissipation ◽  
Lattice Mismatch ◽  
Lead Telluride ◽  
Amorphous Layer ◽  
Interface Layer ◽  
Phonon Transport ◽  
Nanoscale Systems ◽  
Phonon Group Velocity

AbstractManaging heat dissipation is a necessity for nanoscale electronic devices with high-density interfaces, but despite considerable effort, it has been difficult to establish the phonon transport physics at the interface due to a “complex” interface layer. In contrast, the amorphous/epitaxial interface is expected to have almost no “complex” interface layer due to the lack of lattice mismatch strain and less associated defects. Here, we experimentally observe the extremely-small interface thermal resistance per unit area at the interface of the amorphous-germanium sulfide/epitaxial-lead telluride superlattice (~0.8 ± 4.0 × 10‒9 m2KW−1). Ab initio lattice dynamics calculations demonstrate that high phonon transmission through this interface can be predicted, like electron transport physics, from large vibron-phonon density-of-states overlapping and phonon group velocity similarity between propagon in amorphous layer and “conventional” phonon in crystal. This indicates that controlling phonon (or vibron) density-of-states and phonon group velocity similarity can be a comprehensive guideline to manage heat conduction in nanoscale systems.

scholarly journals Quasiparticle scattering and local density of states in thed-density-wave phase

2004 ◽  
Vol 69 (13) ◽  
Author(s):  
Cristina Bena ◽  
Sudip Chakravarty ◽  
Jiangping Hu ◽  
Chetan Nayak
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Density Wave ◽  
Local Density Of States ◽  
Wave Phase ◽  
Quasiparticle Scattering

scholarly journals A comprehensive dispersion model of surface wave phase and group velocity for the globe

2014 ◽  
Vol 199 (1) ◽  
pp. 113-135 ◽  
Author(s):  
Zhitu Ma ◽  
Guy Masters ◽  
Gabi Laske ◽  
Michael Pasyanos
Keyword(s):  
Surface Wave ◽  
Group Velocity ◽  
Dispersion Model ◽  
Wave Phase

Review onFull Wave Phase Analysis

1993 ◽  
Vol 6 (3) ◽  
pp. 795-797
Author(s):  
Shao-Quan Zhang
Keyword(s):  
Phase Analysis ◽  
Wave Phase

The intermittent excitation of geodesic acoustic mode by resonant Instanton of electron drift wave envelope in L-mode discharge near tokamak edge

2021 ◽  
Author(s):  
Liu Zhao-Yang ◽  
Zhang Yang-Zhong ◽  
Swadesh Mitter Mahajan ◽  
Liu A-Di ◽  
Zhou Chu ◽  
...  
Keyword(s):  
Group Velocity ◽  
Reynolds Stress ◽  
Traveling Wave ◽  
Zonal Flow ◽  
Acoustic Mode ◽  
Flow Equation ◽  
Electron Drift ◽  
Drift Wave ◽  
Wave Phase ◽  
Geodesic Acoustic Mode

Abstract There are two distinct phases in the evolution of drift wave envelope in the presence of zonal flow. A long-lived standing wave phase, which we call the Caviton, and a short-lived traveling wave phase (in radial direction) we call the Instanton. Several abrupt phenomena observed in tokamaks, such as intermittent excitation of geodesic acoustic mode (GAM) shown in this paper, could be attributed to the sudden and fast radial motion of Instanton. The composite drift wave – zonal flow system evolves at the two well-separate scales: the micro and the meso-scale. The eigenmode equation of the model defines the zero order (micro-scale) variation; it is solved by making use of the two dimensional (2D) weakly asymmetric ballooning theory (WABT), a theory suitable for modes localized to rational surface like drift waves, and then refined by shifted inverse power method, an iterative finite difference method. The next order is the equation of electron drift wave (EDW) envelope (containing group velocity of EDW) which is modulated by the zonal flow generated by Reynolds stress of EDW. This equation is coupled to the zonal flow equation, and numerically solved in spatiotemporal representation; the results are displayed in self-explanatory graphs. One observes a strong correlation between the Caviton-Instanton transition and the zero-crossing of radial group velocity of EDW. The calculation brings out the defining characteristics of the Instanton: it begins as a linear traveling wave right after the transition. Then, it evolves to a nonlinear stage with increasing frequency all the way to 20 kHz. The modulation to Reynolds stress in zonal flow equation brought in by the nonlinear Instanton will cause resonant excitation to GAM. The intermittency is shown due to the random phase mixing between multiple central rational surfaces in the reaction region.

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