Lattice Wave Dispersion Relation in Two-Dimensional Hexagonal Crystals with Charge Fluctuation

2005 ◽  
Author(s):  
B. Farokhi
Keyword(s):  
Dispersion Relation ◽  
Wave Dispersion ◽  
Charge Fluctuation ◽  
Two Dimensional ◽  
Lattice Wave ◽  
Hexagonal Crystals

scholarly journals Strong second harmonic generation in SiC, ZnO, GaN two-dimensional hexagonal crystals from first-principles many-body calculations

2015 ◽  
Vol 17 (14) ◽  
pp. 9533-9540 ◽  
Author(s):  
C. Attaccalite ◽  
A. Nguer ◽  
E. Cannuccia ◽  
M. Grüning
Keyword(s):  
Second Harmonic Generation ◽  
Real Time ◽  
Harmonic Generation ◽  
First Principles ◽  
Function Theory ◽  
Second Harmonic ◽  
Two Dimensional ◽  
Many Body ◽  
Ti:Sapphire Laser ◽  
Hexagonal Crystals

By using a real-time approach based on Green's function theory we predict a strong second-harmonic generation (SHG) for frequencies at which Ti:sapphire laser operates and for which the materials are transparent.

Attenuation of longitudinal electro-acoustic waves in a plasma

1974 ◽  
Vol 11 (1) ◽  
pp. 37-49
Author(s):  
R. J. Papa ◽  
P. Lindstrom
Keyword(s):  
Dispersion Relation ◽  
Electric Field ◽  
Acoustic Waves ◽  
Collision Frequency ◽  
Wave Dispersion ◽  
Signal Frequency ◽  
Variable Theory ◽  
Longitudinal Waves ◽  
Confluent Hypergeometric Functions ◽  
Linearized Boltzmann Equation

There are several practical situations in partially ionized plasmas when both collisionless (Landau) damping and electron-neutral collisions contribute to the attenuation of longitudinal waves. The longitudinal-wave dispersion relation is derived from Maxwell's equations and the linearized Boltzmann equation, in which electron-neutral collisions are represented by a Bhatnagar–Gross–Krook model that conserves particles locally. (The dispersion relation predicts that, for a given signal frequency ώ), an infinite number of complex wavenumbers kn can exist. Using Fourier–Laplace transform techniques, an integral representation for the electric field of the longitudinal waves is readily derived. Then, using theorems from complex variable theory, a modal expansion of the electric field can be made in terms of an infinite sum of confluent hypergeometric functions, whose arguments are proportional to the complex wavenumbers kn. It is demonstrated numerically that the spatial integral of the square of the electric field amplitude decreases as the electron-neutral collision frequency increases. Also, the amount of energy contained in the first few (lowest) modes, and the coupling between the modes, is examined as a function of plasma frequency, signal frequency and collision frequency.

Effect of the number of defect particles on the structure and dispersion relation of a two-dimensional dust lattice system

2021 ◽  
Author(s):  
Rangyue Zhang ◽  
Guannan Shi ◽  
Hanyu Tang ◽  
Yang Liu ◽  
Yanhong Liu ◽  
...  
Keyword(s):  
Dispersion Relation ◽  
Lattice System ◽  
Two Dimensional
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