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.

scholarly journals Thermal Properties of Yttrium Aluminum Garnett From Molecular Dynamics Simulations

2011 ◽  
Author(s):  
Majid S. al-Dosari ◽  
D. G. Walker
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Specific Heat ◽  
Molecular Dynamics Simulations ◽  
Yttrium Aluminum Garnet ◽  
System Size ◽  
Yttrium Aluminum ◽  
Dynamics Simulations

Yttrium Aluminum Garnet (YAG, Y3Al5O12) and its varieties have applications in thermographic phosphors, lasing mediums, and thermal barriers. In this work, thermal properties of crystalline YAG where aluminum atoms are substituted with gallium atoms (Y3(Al1−xGax)5O12) are explored with molecular dynamics simulations. For YAG at 300K, the simulations gave values close to experimental values for constant-pressure specific heat, thermal expansion, and bulk thermal conductivity. For various values of x, the simulations predicted no change in thermal expansion, an increase in specific heat, and a decrease in thermal conductivity for x = 50%. Furthermore, the simulations predicted a decrease in thermal conductivity with decreasing system size.

scholarly journals Boron–graphdiyne: a superstretchable semiconductor with low thermal conductivity and ultrahigh capacity for Li, Na and Ca ion storage

2018 ◽  
Vol 6 (23) ◽  
pp. 11022-11036 ◽  
Author(s):  
Bohayra Mortazavi ◽  
Masoud Shahrokhi ◽  
Xiaoying Zhuang ◽  
Timon Rabczuk
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Single Layer ◽  
Functional Theory ◽  
Ion Storage ◽  
Ca Ions ◽  
Dynamics Simulations

We conducted density functional theory and classical molecular dynamics simulations to study the mechanical, thermal conductivity and stability, electronic and optical properties of single-layer boron–graphdiyne, a novel synthesized 2D material. Our first-principles results reveal the outstanding prospect of boron–graphdiyne as an anode material with ultrahigh charge capacities for Li, Na and Ca ions storage.

scholarly journals In search of new reconstructions of (001) α-quartz surface: a first principles study

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55599-55603 ◽  
Author(s):  
Oleksandr I. Malyi ◽  
Vadym V. Kulish ◽  
Clas Persson
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Molecular Dynamics Simulations ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Quartz Surface ◽  
Functional Theory ◽  
First Principles Study ◽  
Dynamics Simulations

Using Born–Oppenheimer molecular dynamics simulations and “static” density functional theory calculations, reconstructions of the (001) α-quartz surface are studied in detail.

QM/MM molecular dynamics simulations of the hydration of Mg(II) and Zn(II) ions

2013 ◽  
Vol 91 (7) ◽  
pp. 552-558 ◽  
Author(s):  
Saleh Riahi ◽  
Benoît Roux ◽  
Christopher N. Rowley
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Density Functional ◽  
Distribution Functions ◽  
Water Model ◽  
Polarizable Force Field ◽  
Water Solvent ◽  
Dynamics Simulations ◽  
Good Agreement

The hydration of Mg2+ and Zn2+ is examined using molecular dynamics simulations using 3 computational approaches of increasing complexity: the CHARMM nonpolarizable force field based on the TIP3P water model, the Drude polarizable force field based on the SWM4-NDP water model, and a combined QM/MM approach in which the inner coordination sphere is represented using a high-quality density functional theory (DFT) model (PBE/def2-TZVPP), and the remainder of the bulk water solvent is represented using the polarizable SWM4-NDP water model. The characteristic structural distribution functions (radial, angular, and tilt) are comparedand show very good agreement between the polarizable force field and QM/MM approaches. They predict an average Mg–O distance of 2.11 Å and an Zn–O distance of 2.13 Å, in good agreement with the available experimental neutron scattering and EXAFS data, while the Mg–O distances calculated using the nonpolarizable force field are 0.1 Å too short. Mg2+ (aq) and Zn2+ (aq) both have a coordination number of 6 and have a remarkably similar octahedral coordination mode, despite the chemical differences between these ions. Thermodynamic integration was used to calculate the relative hydration free energies of these ions (ΔΔGhydr). The nonpolarizable model is in error by 60 kcal mol– 1 and incorrectly predicts that Mg2+ has the more negative hydration energy. The Drude polarizable model predicts a ΔΔGhydr of only –13.2 kcal kcal mol– 1, an improvement over the results of the nonpolarizable force field, but still signficantly different than the experimental value of –30.1 kcal mol–1. The combined QM/MM approach performs much better, predicting a ΔΔGhydr of –34.8 kcal mol–1 in excellent agreement with experiment. These calculations support the experimental observation that Zn2+ has more favourable solvation free energy than Mg2+ despite having a very similar solvation structure.

scholarly journals Effect of vacancy concentration on the lattice thermal conductivity of CH3NH3PbI3: a molecular dynamics study

RSC Advances ◽  
2021 ◽  
Vol 11 (54) ◽  
pp. 34015-34023
Author(s):  
Song-Nam Hong ◽  
Chol-Jun Yu ◽  
Un-Gi Jong ◽  
Song-Hyok Choe ◽  
Yun-Hyok Kye
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Dynamics Simulations

Molecular dynamics simulations with the MYP force field were performed to determine the thermal conductivity of perfect and defective bulk MAPbI3. Thermal conductivity was found to decrease overall as the vacancy concentration increased.

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