Molecular Dynamics Simulations of Thermal Conductivity of Germanene Nanoribbons (GeNR) with Armchair and Zigzag Chirality

2015 ◽  
Vol 772 ◽  
pp. 67-71 ◽  
Author(s):  
Marissa A. Balatero ◽  
Giovanni J. Paylaga ◽  
Naomi T. Paylaga ◽  
Rolando V. Bantaculo
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Large Scale ◽  
Massively Parallel ◽  
Fixed Temperature ◽  
New Material ◽  
Silicene Nanoribbons ◽  
Dynamics Simulations ◽  
Conductivity Behavior ◽  
Nanoscale Level

Germanene, an allotrope of germanium which is a two dimensional material withsp2hybridization, has almost the same properties with graphene except for its buckled structure. In this study, germanium nanoribbon (GeNR) is use for it is still a new material for nanoscale level of research. In this paper, we investigate the effect of chirality on the thermal conductivity of zigzag GeNR (ZGeNR) and armchair GeNR (AGeNR) chiralities using equilibrium molecular dynamics with varied lengths at fixed temperature and varied temperatures at fixed length. The simulations were carried out in Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) using Tersoff potential for the Ge-Ge interactions. The thermal conductivity is calculated using Green-Kubo method. It is found that the chirality can affect the thermal conductivity of GeNR. Our results show that thermal conductivity of AGeNR is higher than ZGeNR in both increasing temperatures and lengths similar to the thermal conductivity behavior obtained in silicene nanoribbons [Int. J. Mech. Mater. Des. 9 (2013) 105].

IMD: A Software Package for Molecular Dynamics Studies on Parallel Computers

1997 ◽  
Vol 08 (05) ◽  
pp. 1131-1140 ◽  
Author(s):  
J. Stadler ◽  
R. Mikulla ◽  
H.-R. Trebin
Keyword(s):  
Molecular Dynamics ◽  
Software Package ◽  
Large Scale ◽  
Md Simulation ◽  
Parallel Computers ◽  
Massively Parallel ◽  
Massively Parallel Computers ◽  
Communication Scheme ◽  
And Performance ◽  
Dynamics Simulations

We report on implementation and performance of the program IMD, designed for short range molecular dynamics simulations on massively parallel computers. After a short explanation of the cell-based algorithm, its extension to parallel computers as well as two variants of the communication scheme are discussed. We provide performance numbers for simulations of different sizes and compare them with values found in the literature. Finally we describe two applications, namely a very large scale simulation with more than 1.23×109 atoms, to our knowledge the largest published MD simulation up to this day and a simulation of a crack propagating in a two-dimensional quasicrystal.

Anomalous Effect on the Phononic Thermal Conductivity of Silicene Nanoribbon by Hydrogenation

2015 ◽  
Vol 1105 ◽  
pp. 110-114 ◽  
Author(s):  
Emmanuel Dioresma Monterola ◽  
Naomi Tabudlong Paylaga ◽  
Giovanni Jariol Paylaga ◽  
Rolando Viño Bantaculo
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Silicon Nanowires ◽  
Large Scale ◽  
Massively Parallel ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Anomalous Effect ◽  
Hydrogenated Silicon ◽  
Out Of Plane

Silicene is a two-dimensional (2D) allotrope of silicon known to have a lower thermal conductivity than graphene; thus, more suitable for thermoelectric applications. This paper investigates the effect of hydrogenation on the thermal conductivity of silicene nanoribbon (SiNR) using equilibrium molecular dynamics (EMD) simulations. The simulations were carried out in Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) using a modified Tersoff potential that considers both Si-Si and Si-H interactions. The thermal conductivity of fully hydrogenated silicene nanoribbon (H-SiNR), also known as silicane nanoribbon, was found to be higher than that of pristine SiNR in all the temperatures and dimensions considered here. This anomalous enhancement in the thermal conductivity is similar to that found in hydrogenated silicon nanowires (H-SiNWs). A mechanism for this anomalous effect has been proposed relating the hydrogenation of SiNR with the stiffening and increase of the acoustic out-of-plane flexural (ZA) phonon modes. Also, for both SiNR and H-SiNR, the thermal conductivities generally increase as the dimensions are increased while they generally decrease as the temperatures are increased, in agreement to other reports.

Molecular Dynamics Simulation of the Thermal Conductivity of Silicon-Germanene Nanoribbon (SiGeNR): A Comparison with Silicene Nanoribbon (SiNR) and Germanene Nanoribbon (GeNR)

2015 ◽  
Vol 1105 ◽  
pp. 285-289 ◽  
Author(s):  
Jessa Mae P. Tagalog ◽  
Cachey Girly Alipala ◽  
Giovanni J. Paylaga ◽  
Naomi T. Paylaga ◽  
Rolando V. Bantaculo
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Silicon Germanium ◽  
Large Scale ◽  
Room Temperature ◽  
Single Layer ◽  
Dynamics Simulation ◽  
Two Dimensional ◽  
Silicon And Germanium ◽  
Dynamics Simulations

This study examines the nature of thermal transport properties of single layer two-dimensional honeycomb structures of silicon-germanene nanoribbon (SiGeNR), silicene nanoribbon (SiNR) and germanene nanoribbon (GeNR) which have not yet been characterized experimentally. SiGeNR, SiNR and GeNR are the allotropes of silicon-germanium, silicon and germanium, respectively, withsp2hybridization. The thermal conductivity of the materials has been investigated using Tersoff potential through LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) by performing the molecular-dynamics simulations. The temperature is varied (50 K, 77 K, 150 K, 300 K, 500 K, 700 K, 1000 K, and 1200 K) with fixed nanoribbon dimension of 50 nm × 10 nm. The length is also varied (10 nm, 20 nm, 30 nm, 40 nm, and 50 nm) while the temperature is fixed at room temperature and the width is also fixed at 10 nm. The obtained results showed that the thermal conductivity of SiGeNR at room temperature is approximately 10 times higher than GeNR and approximately 6 times higher compared to SiNR. The thermal conductivity increases as the temperature is increased from 50 K – 300 K, and as the temperature is further increased, the thermal conductivity decreases with temperature. Moreover, the thermal conductivity in SiGeNR, SiNR, and GeNR increases as the length is being increased. Predicting new features of SiGeNR, SiNR and GeNR open new possibilities for nanoelectronic device applications of group IV two-dimensional materials.

scholarly journals EQUILIBRIUM MOLECULAR DYNAMICS CALCULATIONS OF THERMAL CONDUCTIVITY: A “HOW-TO” FOR THE BEGINNERS

2020 ◽  
Vol 9 (1) ◽  
pp. 11-25
Author(s):  
Jude S. Alexander ◽  
Christopher Maxwell ◽  
Jeremy Pencer ◽  
Mouna Saoudi
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Large Scale ◽  
Interatomic Potential ◽  
Negative Impact ◽  
Significant Risk ◽  
Nonequilibrium Molecular Dynamics ◽  
Atomistic Modelling ◽  
Dynamics Simulations

The ready availability of codes such as LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) for molecular dynamics simulations has opened up the realm of atomistic modelling to novice code users with an interest in computational materials modelling but who lack the appropriate theoretical or computational background. As such, there is significant risk of the “user effect” having a negative impact on the quality of results obtained using such codes. Here, we present a “how-to” procedure for equilibrium molecular dynamics-based nuclear fuel thermal conductivity calculations using the Green–Kubo method with an interatomic potential developed by Cooper et al. [ 1 ]. The various steps of the simulation are identified and explained, along with criteria to assess the quality of the intermediate and final results, discussion of some problems that can arise during a simulation, and some inherent limitations of the method. Calculated thermal conductivities for UO2 and ThO2 will be compared with the available experimental data and also with similar thermal conductivity calculations using nonequilibrium molecular dynamics, reported in the open literature.

Mapping thermal resistance around vacancy defects in graphite

2013 ◽  
Vol 1543 ◽  
pp. 65-70 ◽  
Author(s):  
Laura de Sousa Oliveira ◽  
P. Alex Greaney
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
High Purity ◽  
In Silico ◽  
Large Scale ◽  
Nuclear Industry ◽  
Vacancy Defects ◽  
Dynamics Simulations ◽  
The Impact ◽  
Morphology Changes

ABSTRACTHigh purity bulk graphite is applicable in many capacities in the nuclear industry. The thermal conductivity of graphite has been found to vary as a function of how its morphology changes on the nanoscale, and the type and number of defects present. We compute thermal conductivities at the nanolevel using large scale classical molecular dynamics simulations and by employing the Green-Kubo method in a set of in silico experiments geared towards understanding the impact of defects in the thermal conductivity of graphite. We present the results obtained for systems with 1– 3 vacancies, and compile a summary of some of the methods applied and difficulties encountered.

Thermal Conductivity of Silicon-Graphene Nanoribbon (SiGNR): An Equilibrium Molecular Dynamics (EMD) Simulation

2015 ◽  
Vol 1105 ◽  
pp. 280-284 ◽  
Author(s):  
Cachey Girly G. Alipala ◽  
Giovanni J. Paylaga ◽  
Naomi T. Paylaga ◽  
Rolando V. Bantaculo
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Large Scale ◽  
Room Temperature ◽  
Mean Free Path ◽  
Graphene Nanoribbon ◽  
Fixed Temperature ◽  
Dependent Behavior ◽  
Two Dimensional Materials ◽  
20 Nm

Silicon-graphene nanoribbon (SiGNR), an allotrope of silicon carbide withsp2hybridization, gains interest nowadays in the world of two-dimensional materials. In this study, the thermal conductivity of SiGNR is investigated and compared to that of graphene nanoribbon (GNR) and silicene nanoribbon (SiNR). Molecular Dynamics using Tersoff potential through Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) using the Green-Kubo method is employed to predict the thermal conductivity of silicon-graphene materials with armchair chirality. The temperature is varied from 50 K, 77 K, 150 K, 300 K, 500 K, 700 K, 1000 K, 1200 K, and 1500 K with a fixed width of 10 nm and length of 50 nm. The length of the materials is also varied from 10 nm, 20 nm, 30 nm, 40 nm and 50 nm with a fixed temperature of 300 K. Our results show that the thermal conductivity of SiGNR is higher than that of GNR and is approximately 50% larger at room temperature, which may be attributed to the presence of Si atoms inducing larger flexural phonon density of states than in GNR and SiNR. Also, the thermal conductivity of SiGNR follows the same length-dependent behavior of GNR due to its long mean free path. This study presents new insights into the thermal properties of silicon-graphene which will be significant for nanoelectronic applications.

Massively Parallel Molecular Dynamics Simulations of Two-dimensional Materials at High Strain Rates

1992 ◽  
Vol 291 ◽  
Author(s):  
Norman J. Wagner ◽  
Brad Lee Holian
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Large Scale ◽  
Spall Strength ◽  
Computer Experiments ◽  
Dislocation Dynamics ◽  
Parallel Computer ◽  
Massively Parallel ◽  
Connection Machine ◽  
Dynamics Simulations

ABSTRACTLarge scale molecular dynamics simulations on a massively parallel computer are performed to investigate the mechanical behavior of 2-dimensional materials. A model embedded atom many- body potential is examined, corresponding to “ductile” materials. A parallel MD algorithm is developed to exploit the architecture of the Connection Machine, enabling simulations of > 106atoms. A model spallation experiment is performed on a 2-D triagonal crystal with a well-defined nanocrystalline defect on the spall plane. The process of spallation is modelled as a uniform adiabatic expansion. The spall strength is shown to be proportional to the logarithm of the applied strain rate and a dislocation dynamics model is used to explain the results. Good predictions for the onset of spallation in the computer experiments is found from the simple model. The nanocrystal defect affects the propagation of the shock front and failure is enhanced along the grain boundary.

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.

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