Atomic-Scale Probing of Defect-Assisted Ga Intercalation Through Graphene Using ReaxFF Molecular Dynamics Simulations

2021 ◽  
Author(s):  
Nadire Nayir ◽  
Mert Y. Sengul ◽  
Anna L. Costine ◽  
Petra Reinke ◽  
Siavash Rajabpour ◽  
...  
2019 ◽  
Vol 21 (24) ◽  
pp. 13099-13108 ◽  
Author(s):  
Susanna Monti ◽  
Jiya Jose ◽  
Athira Sahajan ◽  
Nandakumar Kalarikkal ◽  
Sabu Thomas

Functionalized gold nanoparticles for antibiotic drug delivery: from the nanoscale to the atomic scale.


MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3381-3398
Author(s):  
Xiaowang Zhou

ABSTRACTAtomic scale defects critically limit performance of semiconductor materials. To improve materials, defect effects and defect formation mechanisms must be understood. In this paper, we demonstrate multiple examples where molecular dynamics simulations have effectively addressed these issues that were not well addressed in prior experiments. In the first case, we report our recent progress on modelling graphene growth, where we found that defects in graphene are created around periphery of islands throughout graphene growth, not just in regions where graphene islands impinge as believed previously. In the second case, we report our recent progress on modelling TlBr, where we discovered that under an electric field, edge dislocations in TlBr migrate in both slip and climb directions. The climb motion ejects extensive vacancies that can cause the rapid aging of the material seen in experiments. In the third case, we discovered that the growth of InGaN films on (0001) surfaces suffers from a serious polymorphism problem that creates enormous amounts of defects. Growth on ($11\bar{2}0$) surfaces, on the other hand, results in single crystalline wurtzite films without any of these defects. In the fourth case, we first used simulations to derive dislocation energies that do not possess any noticeable statistical errors, and then used these error-free methods to discover possible misuse of misfit dislocation theory in past thin film studies. Finally, we highlight the significance of molecular dynamics simulations in reducing defects in the design space of nanostructures.


2000 ◽  
Vol 644 ◽  
Author(s):  
Xi-Yong Fu ◽  
Michael L. Falk ◽  
David A. Rigney

AbstractTribological properties of bulk metallic glass Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 were studied experimentally using a pin/disk geometry without lubrication. Experimental observations were compared with 2D molecular dynamics simulations of amorphous material in sliding contact. The friction coefficient and the wear rate of bulk metallic glass (BMG) depend on normal load and test environment. The sliding of annealed BMG re-amorphizes devitrified material. A mechanically mixed layer is generated during sliding; this layer has enhanced oxygen content if the sliding is in air. The MD simulations show that atomic scale mixing occurs across the sliding interface. The growth kinetics of the mixing process scales with the square root of time. In the simulations, a low density region is generated near the sliding interface; it corresponds spatially to the softer layer detected in experiments. Subsurface displacement profiles produced by sliding and by simulation are very similar and are consistent with the flow patterns expected from a simple Navier-Stokes analysis when the stress state involves both compression and shear.


MRS Bulletin ◽  
2007 ◽  
Vol 32 (11) ◽  
pp. 920-926 ◽  
Author(s):  
Ronald E. Miller ◽  
Ellad B. Tadmor

AbstractMany aspects of materials deformation and failure are controlled by atomic-scale phenomena that can be explored using molecular statics and molecular dynamics simulations. However, many of these phenomena involve processes on multiple length scales with the result that full molecular statics/molecular dynamics simulations of the entire system are too large to be tractable. In this review, we discuss hybrid models that perform molecular statics/molecular dynamics simulations “without all the atoms,” aimed at retaining atomistic detail at a fraction of the computational cost. These methods couple a fully atomistic model in critical regions to regions described by less-expensive continuum methods where they can provide an adequate representation of the important physics. We give an overview of the challenges such models present, with a focus on recent work to address issues of dynamics and finite (non-zero) temperature.


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