Molecular Dynamics Simulations and Kapitza Conductance Prediction of Si/Au Systems Using the New Full 2NN MEAM Si/Au Cross-Potential

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Carolina Abs da Cruz ◽  
Patrice Chantrenne ◽  
Xavier Kleber
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Physical Vapor Deposition ◽  
Local Density ◽  
Mean Free Path ◽  
Nonequilibrium Molecular Dynamics ◽  
Kapitza Conductance ◽  
Dynamics Simulations ◽  
Good Agreement

Superlattices made by superposing dielectric and metal nanolayers are of great interest as their small size restricts the thermal energy carrier mean free path, decreasing the thermal conductivity and thereby increasing the thermoelectric figure of merit. It is, therefore, essential to predict their thermal conductivity. Potentials for Au and Si are discussed, and the potential of second nearest-neighbor modified embedded atom method (2NN MEAM) is chosen as being the best for simulating heat transfer in Si/Au systems. Full 2NN MEAM Si/Au cross-potential parameterization is developed, and the results are compared with ab initio calculations to test its ability to reproduce local density approximation (LDA) calculations. Volume-constant (NVT) molecular dynamics simulations are performed to deposit Au atoms on an Si substrate by physical vapor deposition, and the results of the intermixing zone are in good agreement with the Cahn and Hilliard theory. Nonequilibrium molecular dynamics simulations are performed for an average temperature of 300 K to determine the Kapitza conductance of Si/Au systems, and the obtained value of 158 MW/m 2 K is in good agreement with the results of Komarov et al. for Au deposited on isotopically pure Si- 28 and natural Si, with values ranging between 133 and 182 MW/m2 K.

Thermal Conductivity of Amorphous and Crystalline SiO2 Nano-Films from Molecular Dynamics Simulations

2012 ◽  
Vol 501 ◽  
pp. 64-69 ◽  
Author(s):  
Yan He ◽  
Yuan Zheng Tang ◽  
Man Ding ◽  
Lian Xiang Ma
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Film Thickness ◽  
Molecular Dynamics Simulations ◽  
Grain Morphology ◽  
Nonequilibrium Molecular Dynamics ◽  
Calculated Temperature ◽  
Dynamics Simulations ◽  
Different Thickness ◽  
Good Agreement

Normal thermal conductivity of amorphous and crystalline SiO2nano-films is calculated by nonequilibrium molecular dynamics (NEMD) simulations in the temperature range from 100 to 700K and thicknesses from 2 to 6nm. The calculated temperature and thickness dependences of thermal conductivity are in good agreement with previous literatures. In the same thickness, higher thermal conductivity is obtained for crystalline SiO2nano-films. And more importantly, for amorphous SiO2nano-films, thickness can be any direction of x, y, z-axis without effect on the normal thermal conductivity, for crystalline SiO2nano-films, the different thickness directions obtain different thermal conductivity results. The different results of amorphous and crystalline SiO2nano-films simply show that film thickness and grain morphology will cause different effects on thermal conductivity.

Molecular Dynamics Simulations and Kaptiza Conductance Prediction of Si/Au Systems Using the New Full 2NN MEAM Si/Au Cross-Potential

2011 ◽  
Author(s):  
Carolina Abs da Cruz ◽  
Patrice Chantrenne ◽  
Xavier Kleber
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Physical Vapor Deposition ◽  
Figure Of Merit ◽  
Local Density ◽  
Thermoelectric Figure ◽  
Average Temperature ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Good Agreement

Superlattices made by superposing dielectric and metal nanolayers are of great interest as their small size may increase the thermoelectric figure of merit. Thus it is essential to predict their thermal conductivity. Potentials for Au and Si are discussed and the potential of 2NN MEAM is chosen as being the best for simulating heat transfer in Si/Au systems. Full 2NN MEAM Si/Au cross-potential parametrization is developed and the results are compared with ab initio calculus to test its ability to reproduce local density approximation (LDA) calculations. NVT molecular dynamics simulations are performed to deposit Au atoms on an Si substrate by physical vapor deposition and the results of the intermixing zone are in good agreement with the Cahn and Hilliard theory. Non-equilibrium molecular dynamics simulations are performed for an average temperature of 300 K to determine the Kaptiza conductance of Si/Au systems, and the value of 188 MW/m2K obtained is in good agreement with the results of Komarov et al. for Au deposited on isotopically-pure Si-28 and natural Si, with values ranging between 133 and 182 MW/m2K.

scholarly journals Ballistic Heat Transport in Nanocomposite: The Role of the Shape and Interconnection of Nanoinclusions

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1982
Author(s):  
Paul Desmarchelier ◽  
Alice Carré ◽  
Konstantinos Termentzidis ◽  
Anne Tanguy
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Free Path ◽  
Mean Free Path ◽  
Strong Increase ◽  
Moderate Increase ◽  
Energy Propagation ◽  
The Mean ◽  
Dynamics Simulations

In this article, the effect on the vibrational and thermal properties of gradually interconnected nanoinclusions embedded in an amorphous silicon matrix is studied using molecular dynamics simulations. The nanoinclusion arrangement ranges from an aligned sphere array to an interconnected mesh of nanowires. Wave-packet simulations scanning different polarizations and frequencies reveal that the interconnection of the nanoinclusions at constant volume fraction induces a strong increase of the mean free path of high frequency phonons, but does not affect the energy diffusivity. The mean free path and energy diffusivity are then used to estimate the thermal conductivity, showing an enhancement of the effective thermal conductivity due to the existence of crystalline structural interconnections. This enhancement is dominated by the ballistic transport of phonons. Equilibrium molecular dynamics simulations confirm the tendency, although less markedly. This leads to the observation that coherent energy propagation with a moderate increase of the thermal conductivity is possible. These findings could be useful for energy harvesting applications, thermal management or for mechanical information processing.

Thermal Conductivity of Graphene on Nanostructure Size from Nonequilibrium Molecular Dynamics Simulations

2020 ◽  
Vol 17 (4) ◽  
pp. 1566-1570
Author(s):  
Xianqi Wei ◽  
Zelin Li ◽  
Junchen Lu ◽  
Shunlong Xu ◽  
Yuancheng Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Management ◽  
Strong Dependence ◽  
Thermal Conductance ◽  
Mean Free Path ◽  
Dynamics Simulation ◽  
Nonequilibrium Molecular Dynamics ◽  
Edge Type ◽  
Dynamics Simulations

Thermal transport of graphene occupies a unique place in thermal management of electronic devices, especially for nanosize devices with high-density integration and high dissipated power. The structure of graphene on nanometer scale changes its thermal conductance. Here, the thermal characters of graphene have been researched by nonequilibrium molecular dynamics simulation (NEMDS) at room temperature. Special attention is focused on the edge type (zigzag or armchair) and nanostructure size dependence of conductivity for heat. The consequences suggest that the thermal conductivity of zigzag edge has been higher than that of armchair, which is because of the higher phonon group velocities. Furthermore, thermal conductivity shows a rising tendency, when the model is calculated from length of 21.84 nm to 43.78 nm. The result indicates that the thermal property performs a strong dependence on nanostructure size which is less than phonon mean free path (775 nm). Our research highlights the significance of structure attribute relationships together with providing useful guideline in calculations for nanosize devices thermal management.

Thermal Conductivity of Hexagonal SiC Nanowire by Nonequilibrium Molecular Dynamics Simulations

2014 ◽  
Vol 487 ◽  
pp. 102-105
Author(s):  
Zan Wang ◽  
Hua Wei Guan ◽  
Ke Dong Bi
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Free Path ◽  
Density Functional ◽  
Mean Free Path ◽  
Nonequilibrium Molecular Dynamics ◽  
Functional Theory ◽  
Sic Nanowires ◽  
Dynamics Simulations ◽  
Dynamics Method

Using nonequilibrium Molecular Dynamics method, thermal properties of hexagonal 4H-SiC and 6H-SiC nanowires are investigated. The quantum errors between realistic temperatures and Molecular dynamics temperatures are rectified based on Density Functional Theory. Thermal conductivities of 4H-SiC and 6H-SiC nanowires are both simulated from 50K to 800K. The scale effect on the thermal conductivity of nanowire is also investigated by varying the nanowires length from 10nm to 130nm. Results indicate, if the length of phonon mean free path is shorter than that of nanowire, phonon-surface scattering will surpass boundary scattering to contribute thermal resistances. Therefore, the thermal conductivity of 4H-SiC or 6H-SiC nanowire is mainly determined by the comparability between the length of nanowires and phonon mean free path.

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