Interatomic force constants from first principles: The case of α-quartz

1994 ◽  
Vol 50 (17) ◽  
pp. 13035-13038 ◽  
Author(s):  
X. Gonze ◽  
J.-C. Charlier ◽  
D.C. Allan ◽  
M.P. Teter
Keyword(s):  
First Principles ◽  
Force Constants ◽  
Interatomic Force

scholarly journals First-Principles-Based Interatomic Potential for SI and Its Thermal Conductivity

2011 ◽  
Author(s):  
Keivan Esfarjani ◽  
Gang Chen ◽  
Asegun Henry
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Properties ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
First Principles ◽  
Density Functional ◽  
Interatomic Potential ◽  
Force Constants ◽  
Dynamics Simulations

Based on first-principles density-functional calculations, we have developed and tested a force-field for silicon, which can be used for molecular dynamics simulations and the calculation of its thermal properties. This force field uses the exact Taylor expansion of the total energy about the equilibrium positions up to 4th order. In this sense, it becomes systematically exact for small enough displacements, and can reproduce the thermodynamic properties of Si with high fidelity. Having the harmonic force constants, one can easily calculate the phonon spectrum of this system. The cubic force constants, on the other hand, will allow us to compute phonon lifetimes and scattering rates. Results on equilibrium Green-Kubo molecular dynamics simulations of thermal conductivity as well as an alternative calculation of the latter based on the relaxation-time approximation will be reported. The accuracy and ease of computation of the lattice thermal conductivity using these methods will be compared. This approach paves the way for the construction of accurate bulk interatomic potentials database, from which lattice dynamics and thermal properties can be calculated and used in larger scale simulation methods such as Monte Carlo.

First-Principles Calculation of Force Constants and Full Phonon Dispersions

1992 ◽  
Vol 291 ◽  
Author(s):  
Siqing Wei ◽  
M. Y. Chou
Keyword(s):  
First Principles ◽  
Phonon Dispersion ◽  
Local Density ◽  
Real Space ◽  
Force Constants ◽  
First Principles Calculation ◽  
Dynamical Matrix ◽  
Phonon Dispersion Curves ◽  
Super Cell ◽  
Silicon And Germanium

ABSTRACTWe calculated the real-space force constants and full phonon dispersion curves for elemental semiconductors (silicon and germanium) under the local-density approximation with the Hellmann-Feynman forces. The force constants are obtained through super- cell calculations for planar displacements in three different symmetry directions. From these real-space force constants the dynamical matrix for an arbitrary wave vector in the Brillouin zone can be constructed. The procedure is simple in concept and requires no complicated computer programing. It is also possible in principle to handle the anharmonic effects.

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