Shear Flows in Two Dimensional Strongly Coupled Yukawa Liquids: A Large Scale Molecular Dynamics Study

ABSTRACTThe advent of graphene created a revolution in materials science. Because of this there is a renewed interest in other carbon-based structures. Graphene is the ultimate (just one atom thick) membrane. It has been proposed that graphene can work as impermeable membrane to standard gases, such argon and helium. Graphene-like porous membranes, but presenting larger porosity and potential selectivity would have many technological applications. Biphenylene carbon (BPC), sometimes called graphenylene, is one of these structures. BPC is a porous two-dimensional (planar) allotrope carbon, with its pores resembling typical sieve cavities and/or some kind of zeolites. In this work, we have investigated the hydrogenation dynamics of BPC membranes under different conditions (hydrogenation plasma density, temperature, etc.). We have carried out an extensive study through fully atomistic molecular dynamics (MD) simulations using the reactive force field ReaxFF, as implemented in the well-known Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. Our results show that the BPC hydrogenation processes exhibit very complex patterns and the formation of correlated domains (hydrogenated islands) observed in the case of graphene hydrogenation was also observed here. MD results also show that under hydrogenation BPC structure undergoes a change in its topology, the pores undergoing structural transformations and extensive hydrogenation can produce significant structural damages, with the formation of large defective areas and large structural holes, leading to structural collapse.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1105.110 ◽

2015 ◽

Vol 1105 ◽

pp. 110-114 ◽

Cited By ~ 2

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1105.285 ◽

2015 ◽

Vol 1105 ◽

pp. 285-289 ◽

Cited By ~ 1

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.

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Destabilisation of the hexatic phase in systems of hard disks by quenched disorder due to pinning on a lattice

Soft Matter ◽

10.1039/c4sm02876g ◽

2015 ◽

Vol 11 (14) ◽

pp. 2852-2856 ◽

Cited By ~ 22

Author(s):

Weikai Qi ◽

Marjolein Dijkstra

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Large Scale ◽

Quenched Disorder ◽

Hard Disks ◽

Two Dimensional ◽

Hexatic Phase ◽

Event Driven ◽

Melting Mechanism ◽

Dynamics Simulations

We investigate the effect of quenched disorder on the melting mechanism of two-dimensional hard disks using large-scale event-driven molecular dynamics simulations.

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Polarized Thermal Conductivity of Two-Dimensional Dusty Plasmas

10.5772/intechopen.100545 ◽

2021 ◽

Author(s):

Aamir Shahzad ◽

Madiha Naheed ◽

Aadil Mahboob ◽

Muhammad Kashif ◽

Alina Manzoor ◽

...

Keyword(s):

Thermal Conductivity ◽

Molecular Dynamics ◽

Simulation Method ◽

Dusty Plasmas ◽

Two Dimensional ◽

Strongly Coupled ◽

External Force Field ◽

Theoretical Predictions ◽

System Temperature ◽

Non Equilibrium Molecular Dynamics

The computation of thermalt properties of dusty plasmas is substantial task in the area of science and technology. The thermal conductivity (λ) has been computed by applying polarization effect through molecular dynamics (MD) simulations of two dimensional (2D) strongly coupled complex dusty plasmas (SCCDPs). The effects of polarization on thermal conductivity have been measured for a wide range of Coulomb coupling (Γ) and Debye screening (κ) parameters using homogeneous non-equilibrium molecular dynamics (HNEMD) method for suitable system sizes. The HNEMD simulation method is employed at constant external force field strength (F*) and varying polarization effects. The algorithm provides precise results with rapid convergence and minute dimension effects. The outcomes have been compared with earlier available simulation results of molecular dynamics, theoretical predictions and experimental results of complex dusty plasma liquids. The calculations show that the kinetic energy of SCCDPS depends upon the system temperature (≡ 1/Г) and it is independent of higher screening parameter. Furthermore, it has shown that the presented HNEMD method has more reliable results than those obtained through earlier known numerical methods.

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Self-assembly of hairy disks in two dimensions – insights from molecular simulations

Soft Matter ◽

10.1039/c8sm00213d ◽

2018 ◽

Vol 14 (16) ◽

pp. 3115-3126 ◽

Cited By ~ 3

Author(s):

Małgorzata Borówko ◽

Wojciech Rżysko ◽

Stefan Sokołowski ◽

Tomasz Staszewski

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Self Assembly ◽

Large Scale ◽

Molecular Simulations ◽

Two Dimensions ◽

Two Dimensional ◽

Dynamics Simulations

We report the results of large scale molecular dynamics simulations conducted for sparsely grafted disks in two-dimensional systems.

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Kolmogorov flow in two dimensional strongly coupled Yukawa liquid: A molecular dynamics study

Physics of Plasmas ◽

10.1063/1.4934535 ◽

2015 ◽

Vol 22 (10) ◽

pp. 103706 ◽

Cited By ~ 5

Author(s):

Akanksha Gupta ◽

Rajaraman Ganesh ◽

Ashwin Joy

Keyword(s):

Molecular Dynamics ◽

Two Dimensional ◽

Strongly Coupled ◽

Kolmogorov Flow

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A non-linear theory of turbulence onset in a shear flow

Journal of Fluid Mechanics ◽

10.1017/s0022112067001144 ◽

1967 ◽

Vol 29 (4) ◽

pp. 721-729 ◽

Cited By ~ 6

Author(s):

E. M. Hasen

Keyword(s):

Large Scale ◽

Shear Flows ◽

Incompressible Flows ◽

Linear Equations ◽

Finite Amplitude ◽

Small Scale ◽

Two Dimensional ◽

Initial Amplitude ◽

Mean Velocity ◽

Non Linear

Turbulence onset is considered in viscous incompressible flows. Development of fluctuations in an infinite flow with a constant gradient of mean velocity ∂U1/∂x2 = const., U2 = U3 = 0 is rigorously treated.It is shown that two-dimensional eddy fluctuations, with infinitesimal initial amplitude A and scale of initial eddies l, increase in this flow so that the maximum ratio max ε(t)/ε(0) of their energy at the moment t to the initial energy exceeds any prescribed value as the Reynolds number R = (∂U1/∂x2) l2/v increases. The analysis of the non-linear equations obtained in the paper which describe development of fluctuations with a finite amplitude leads to the conclusion that there exists a’ stability barrier’ Ã (R) for the initial amplitude of eddy fluctuations. If A < Ã (R), then fluctuations decay as t → ∞, and if A > Ã(R) the energy of fluctuations does not decay. As R → ∞, Ã(R) → 0 according to the inequalities \[ l(\partial U_1/\partial x_2)K_2/R^{\frac{2}{3}}\leqslant \tilde{A}(R)\leqslant l(\partial U_1/\partial x_2)\,K_1/R^{\frac{2}{3}}. \] It is shown that the non-linear mechanism of preventing turbulence from decay involves generation of large-scale turbulent oscillations which then transmit energy to small-scale motions.The described mechanism of turbulence onset from small eddies in shear flows appears to be of universal character. It is interesting that several qualitative characteristics of turbulence observed in various shear flows can be rigorously deduced even in a model where disturbances remain two-dimensional.

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