Structure, Mechanical Properties, and Thermal Transport in Microporous Silicon Nitride Via Parallel Molecular Dynamics

1995 ◽  
Vol 408 ◽  
Author(s):  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Elastic Constants ◽  
Thermal Transport ◽  
Entire System ◽  
Amorphous Silicon Nitride ◽  
Parallel Molecular Dynamics ◽  
Dynamics Simulations

AbstractMolecular dynamics simulations are performed to investigate structure, mechanical properties, and thermal transport in amorphous silicon nitride under uniform dilation. As the density is lowered, we observe the formation of pores below ρ = 2.6 g/cc and at 2.0 g/cc the largest pore percolates through the entire system. Effects of porosity on elastic constants, phonons and thermal conductivity are investigated. Thermal conductivity and Young's modulus are found to scale as ρ1.5 and ρ3.6, respectively.

Molecular Dynamics Simulations of Nanoindentation of Silicon Nitride

1998 ◽  
Vol 539 ◽  
Author(s):  
Phillip Walsh ◽  
Andrey Omeltchenko ◽  
Hideaki Kikuchi ◽  
Rajiv K. Kalia ◽  
Aiichiro Nakano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Elastic Moduli ◽  
Local Stress ◽  
Md Simulations ◽  
Stress Distributions ◽  
Surface Adhesion ◽  
Amorphous Silicon Nitride ◽  
Dynamics Simulations

AbstractThis is a report of work in progress on 10 million atom Molecular Dynamics (MD) simulations of nanoindentation of crystalline and amorphous silicon nitride (Si3N4). Nanoindentation is used to determine mechanical properties of extremely thin films such as hardness and elastic moduli. We report load-displacement curves for several Si3N4 configurations using an idealized non-deformable indenter and analyze the local stress distributions in the vicinity of the indenter tip. Preliminary results for surface adhesion using Si3N4 for both tip and substrate are also reported.

Mechanical properties of cellulose nanofibrils determined through atomistic molecular dynamics simulations

2012 ◽  
Vol 27 (2) ◽  
pp. 282-286 ◽  
Author(s):  
Jukka Ketoja ◽  
Sami Paavilainen ◽  
James Liam McWhirter ◽  
Tomasz Róg ◽  
Juha Järvinen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Elastic Modulus ◽  
Molecular Dynamics Simulations ◽  
Elastic Constants ◽  
Cellulose Nanofibrils ◽  
Amorphous Cellulose ◽  
Cross Sectional ◽  
Elementary Fibrils ◽  
Dynamics Simulations

Abstract We have carried out atomistic molecular dynamics simulations to study the mechanical properties of cellulose nanofibrils in water and ethanol. The studied elementary fibrils consisted of regions having 34 or 36 cellulose chains whose cross-sectional diameter across the fibril was roughly 3.4 nm. The models used in simulations included both crystalline and non-crystalline regions, where the latter were designed to describe the essentials parts of amorphous cellulose nanofibrils. We examined different numbers of connecting chains between the crystallites, and found out that the elastic constants, inelastic deformations, and strength of the fibril depend on this number. For example, the elastic modulus for the whole fibril can be estimated to increase by 4 GPa for each additional connecting chain.

scholarly journals Impact of screw and edge dislocations on the thermal conductivity of individual nanowires and bulk GaN: a molecular dynamics study

2018 ◽  
Vol 20 (7) ◽  
pp. 5159-5172 ◽  
Author(s):  
Konstantinos Termentzidis ◽  
Mykola Isaiev ◽  
Anastasiia Salnikova ◽  
Imad Belabbas ◽  
David Lacroix ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Transport Properties ◽  
Thermal Transport ◽  
Thermal Transport Properties ◽  
Bulk Gan ◽  
Dynamics Simulations ◽  
Edge Dislocations

The thermal transport properties of nanowires and bulk GaN in the presence of different dislocations using molecular dynamics simulations are reported.

Structure, Mechanical Properties, and Dynamic Fracture in Nanophase Silicon Nitride via Parallel Molecular Dynamics

1996 ◽  
Vol 457 ◽  
Author(s):  
Kenji Tsuruta ◽  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Grain Size ◽  
Silicon Nitride ◽  
Dynamic Fracture ◽  
Elastic Moduli ◽  
Md Simulations ◽  
Multiphase Model ◽  
Order Of Magnitude ◽  
Parallel Molecular Dynamics

ABSTRACTMillion-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si3N4. We find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si3N4 as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si3N4 reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si3N4. This is due to branching and pinning of the crack front by nanoscale microstructures.

scholarly journals Ultimate suppression of thermal transport in amorphous silicon nitride by phononic nanostructure

2020 ◽  
Vol 6 (39) ◽  
pp. eabc0075
Author(s):  
Naoki Tambo ◽  
Yuxuan Liao ◽  
Chun Zhou ◽  
Elizabeth Michiko Ashley ◽  
Kouhei Takahashi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Thermal Transport ◽  
Amorphous Materials ◽  
Vibrational Modes ◽  
Amorphous Silicon Nitride ◽  
Diffusive Boundary ◽  
20 Nm ◽  
The Impact

Engineering the thermal conductivity of amorphous materials is highly essential for the thermal management of future electronic devices. Here, we demonstrate the impact of ultrafine nanostructuring on the thermal conductivity reduction of amorphous silicon nitride (a-Si3N4) thin films, in which the thermal transport is inherently impeded by the atomic disorders. Ultrafine nanostructuring with feature sizes below 20 nm allows us to fully suppress contribution of the propagating vibrational modes (propagons), leaving only the diffusive vibrational modes (diffusons) to contribute to thermal transport in a-Si3N4. A combination of the phonon-gas kinetics model and the Allen-Feldmann theory reproduced the measured results without any fitting parameters. The thermal conductivity reduction was explained as extremely strong diffusive boundary scattering of both propagons and diffusons. These findings give rise to substantial tunability of thermal conductivity of amorphous materials, which enables us to provide better thermal solutions in microelectronic devices.

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