Interaction Between Dislocations and Misfit Interface

2000 ◽  
Vol 634 ◽  
Author(s):  
A. Kuronen ◽  
K. Kaski ◽  
L. F. Perondi ◽  
J. Rintala
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Misfit Dislocation ◽  
Driving Force ◽  
Two Dimensional ◽  
Lennard Jones ◽  
Dynamics Simulations ◽  
Nucleation Of Dislocations

ABSTRACTMechanisms responsible for the formation of a misfit dislocation in a lattice-mismatched system have been studied using Molecular Dynamics simulations of a two-dimensional Lennard-Jones system. Results show clearly how the strain due to the lattice-mismatched interface acts as a driving force for migration of dislocations in the substrate and the overlayer and nucleation of dislocations in the overlayer edges. Moreover, we observe dislocation reactions in which the gliding planes of dislocations change such that they can migrate to the interface.

Substrate induced freezing, melting and depinning transitions in two-dimensional liquid crystalline systems

2022 ◽  
Author(s):  
Bharti bharti ◽  
Debabrata Deb
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystals ◽  
Molecular Dynamics Simulations ◽  
Liquid Crystalline ◽  
Two Dimensional ◽  
One Dimensional ◽  
The One ◽  
Dynamics Simulations

We use molecular dynamics simulations to investigate the ordering phenomena in two-dimensional (2D) liquid crystals over the one-dimensional periodic substrate (1DPS). We have used Gay-Berne (GB) potential to model the...

scholarly journals Shear-rate dependence of thermodynamic properties of the Lennard-Jones truncated and shifted fluid by molecular dynamics simulations

2021 ◽  
Author(s):  
Martin P. Lautenschlaeger ◽  
Hans Hasse
Keyword(s):  
Molecular Dynamics ◽  
Shear Stress ◽  
Shear Rate ◽  
Molecular Dynamics Simulations ◽  
Local Structure ◽  
Rate Dependence ◽  
Lennard Jones ◽  
Fluid Properties ◽  
Dynamics Simulations ◽  
Shear Rate Dependence

It was shown recently that using the two-gradient method, thermal, caloric, and transport properties of fluids under quasi-equilibrium conditions can be determined simultaneously from nonequilibrium molecular dynamics simulations. It is shown here that the influence of shear stresses on these properties can also be studied using the same method. The studied fluid is described by the Lennard-Jones truncated and shifted potential with the cut-off radius r*c = 2.5σ. For a given temperature T and density ρ, the influence of the shear rate on the following fluid properties is determined: pressure p, internal energy u, enthalpy h, isobaric heat capacity cp, thermal expansion coefficient αp, shear viscosity η, and self-diffusion coefficient D. Data for 27 state points in the range of T ∈ [0.7, 8.0] and ρ ∈ [0.3, 1.0] are reported for five different shear rates (γ ̇ ∈ [0.1,1.0]). Correlations for all properties are provided and compared with literature data. An influence of the shear stress on the fluid properties was found only for states with low temperature and high density. The shear-rate dependence is caused by changes in the local structure of the fluid which were also investigated in the present work. A criterion for identifying the regions in which a given shear stress has an influence on the fluid properties was developed. It is based on information on the local structure of the fluid. For the self-diffusivity, shear-induced anisotropic effects were observed and are discussed.

INVESTIGATING DYNAMIC VORTEX TRANSITIONS IN 2D SUPERCONDUCTORS

2009 ◽  
Vol 23 (19) ◽  
pp. 2399-2408
Author(s):  
I. M. OBAIDAT ◽  
U. AL KHAWAJA ◽  
M. BENKRAOUDA
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Driving Force ◽  
Critical Currents ◽  
Flow State ◽  
Pinning Centers ◽  
Average Speed ◽  
Vortex States ◽  
Dynamics Simulations ◽  
2D Superconductors

Extensive molecular dynamics simulations were performed on superconducting samples with periodic square arrays of pinning centers where several strengths, sizes, and densities of the pinning centers were considered. By calculating the average speed of the vortices as the driving force increases, we defined two critical currents that divide the states of the vortices into three different states with respect to the magnitude of the driving current. These vortex states are a pinned state, a disordered flow state where only some of the vortices flow in some vortex channels, and an ordered flow state where all the vortices flow in an ordered and collective manner. We have clarified the roles of the number of vortices, the size, the strength, and the number of pinning centers in these three states at several temperatures.

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