scholarly journals An insight into thermal properties of BC3-graphene hetero-nanosheets: a molecular dynamics study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Zarghami Dehaghani ◽  
Fatemeh Molaei ◽  
Farrokh Yousefi ◽  
S. Mohammad Sajadi ◽  
Amin Esmaeili ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Temperature Gradient ◽  
Grain Boundary ◽  
Thermal Resistance ◽  
Grain Boundaries ◽  
Defect Density ◽  
Topological Defects ◽  
Interfacial Thermal Resistance ◽  
Effect Of Temperature ◽  
Kapitza Resistance

AbstractSimulation of thermal properties of graphene hetero-nanosheets is a key step in understanding their performance in nano-electronics where thermal loads and shocks are highly likely. Herein we combine graphene and boron-carbide nanosheets (BC3N) heterogeneous structures to obtain BC3N-graphene hetero-nanosheet (BC3GrHs) as a model semiconductor with tunable properties. Poor thermal properties of such heterostructures would curb their long-term practice. BC3GrHs may be imperfect with grain boundaries comprising non-hexagonal rings, heptagons, and pentagons as topological defects. Therefore, a realistic picture of the thermal properties of BC3GrHs necessitates consideration of grain boundaries of heptagon-pentagon defect pairs. Herein thermal properties of BC3GrHs with various defects were evaluated applying molecular dynamic (MD) simulation. First, temperature profiles along BC3GrHs interface with symmetric and asymmetric pentagon-heptagon pairs at 300 K, ΔT = 40 K, and zero strain were compared. Next, the effect of temperature, strain, and temperature gradient (ΔT) on Kaptiza resistance (interfacial thermal resistance at the grain boundary) was visualized. It was found that Kapitza resistance increases upon an increase of defect density in the grain boundary. Besides, among symmetric grain boundaries, 5–7–6–6 and 5–7–5–7 defect pairs showed the lowest (2 × 10–10 m2 K W−1) and highest (4.9 × 10–10 m2 K W−1) values of Kapitza resistance, respectively. Regarding parameters affecting Kapitza resistance, increased temperature and strain caused the rise and drop in Kaptiza thermal resistance, respectively. However, lengthier nanosheets had lower Kapitza thermal resistance. Moreover, changes in temperature gradient had a negligible effect on the Kapitza resistance.

Interfacial Thermal Resistance in Nanoscale Heat Transfer

2008 ◽  
Author(s):  
Ganesh Balasubramanian ◽  
Soumik Banerjee ◽  
Ishwar K. Puri
Keyword(s):  
Thermal Resistance ◽  
Interfacial Thermal Resistance ◽  
Kapitza Resistance ◽  
Jones Potential ◽  
Nanoscale Thermal Transport ◽  
Embedded Atom ◽  
Kapitza Length ◽  
Fluid Argon ◽  
Dynamics Simulations ◽  
Potential Parameters

We investigate nanoscale thermal transport across a solid-fluid interface using molecular dynamics simulations. Cooler fluid argon (Ar) is placed between two heated iron (Fe) walls, thereby imposing a temperature gradient within the system. Fluid-fluid and solid-fluid interactions are modeled with Lennard-Jones potential parameters, while Embedded Atom Method (EAM) is used to describe the interactions between solid molecules. The Fe-Ar interaction causes ordering of fluid molecules into quasi-crystalline layers near the walls. This causes temperature discontinuity between these solid-like Ar molecules and the adjacent fluid. The time evolution of the interfacial (Kapitza) thermal resistance (Rk) and Kapitza length (Lk) are observed. The averaged Kapitza resistance (Rk,av) varies with the initial temperature difference between the wall and the fluid (ΔTw) as Rk,av∝ΔTw−0.82.

Crystallinity Dependence of Grain and Grain Boundary Strength of a Bicrystal Structure of Copper

2020 ◽  
Author(s):  
Ken Suzuki ◽  
Yiqing Fan ◽  
Yifan Luo
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Defect Density ◽  
Volume Ratio ◽  
Md Simulations ◽  
Atomic Diffusion ◽  
Strength And Deformation ◽  
Electroplated Copper ◽  
Boundary Strength

Abstract Electroplated copper thin films often contain porous grain boundaries and the volume ratio of porous grain boundaries in the copper thin films is much larger than that in bulk copper. Thus, the lifetime of the interconnection components fabricated by electroplating is strongly dominated by the strength of grain boundaries because final fracture caused by the acceleration of atomic diffusion during electromigration (EM) occurs at grain boundaries in polycrystalline interconnections. It is important, therefore, to quantitatively evaluate the grain boundary strength of electroplated copper films for estimating the lifetime of the interconnection in order to assure the product reliability. In this study, relationship between the strength and crystallinity of electroplated copper thin films was investigated experimentally and theoretically. In order to investigate the relationship between the strength and grain boundary quality, molecular dynamics (MD) simulations were applied to analyze the deformation behavior of a bicrystal sample and its strength. The variation of the strength and deformation property were attributed to the higher defect density around grain boundaries.

Thermal Lagging of Multilayered Structure in Heat-Assisted Magnetic Recording Systems

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Jian Su ◽  
Tingting Tang ◽  
Ruixin Lu ◽  
Peng Yu
Keyword(s):  
Temperature Gradient ◽  
Thermal Resistance ◽  
Magnetic Recording ◽  
Heat Sink ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Interfacial Thermal Resistance ◽  
Disk Drives ◽  
Horizontal Temperature Gradient ◽  
Heat Assisted Magnetic Recording

Abstract In the present study, we numerically investigate the thermal lagging behavior on the hard disk drives in heat-assisted magnetic recording systems via the optical absorption model. The influences of overcoats, laser radius, relative scanning speed, interfacial thermal resistance, and the heat sink layer on the thermal lagging behavior are studied in detail. It is found that the thermal lagging distance, i.e., the horizontal distance between the location of the maximum temperature and the laser center, increases with an increment of speed and/or radius of the laser spot. The overcoats, the interfacial thermal resistance, and the heat sink layer have negligible effects on the lagging distance. Thus, the multilayered disk can be simplified as a single-layer disk for investigating thermal lagging distance. Meanwhile, the horizontal temperature gradient varies with these factors. Different overcoats result in different horizontal temperature gradient owing to the difference of in-plane thermal diffusivity. A laser with a smaller radius or a slower speed leads to a higher horizontal temperature gradient. The thermal resistance influences the horizontal temperature gradient insignificantly. This study may provide useful information for the design of hard disk drives for heat-assisted magnetic recording technologies.

Thermal Properties of Thin Films

1992 ◽  
Vol 284 ◽  
Author(s):  
J. C. Lambropoulos ◽  
S.-S. Hwang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Resistance ◽  
Interfacial Thermal Resistance ◽  
Bulk Solid ◽  
Ceramic Films ◽  
Film Substrate ◽  
Conductivity Of Thin Films

ABSTRACTWe summarize various measurements of the thermal conductivity of thin ceramic films which show that the thermal conductivity of thin films with thickness in the micron and sub-micron range may be up to two orders of magnitude lower than the thermal conductivityof the corresponding bulk solid. The reduction in the thin film effective thermal conductivity is attributed to the interfacial thermal resistance across the film/substrate interface.

INTERFACE THERMAL RESISTANCE BETWEEN FRENKEL-KONTOROVA AND FERMI-PASTA-ULAM LATTICES

2007 ◽  
Vol 21 (23n24) ◽  
pp. 4013-4016 ◽  
Author(s):  
JINGHUA LAN ◽  
LEI WANG ◽  
BAOWEN LI
Keyword(s):  
Temperature Gradient ◽  
Thermal Resistance ◽  
Kapitza Resistance ◽  
Thermal Rectification ◽  
One Dimensional ◽  
Interface Thermal Resistance ◽  
Phonon Spectra ◽  
Qualitative Relationship

By connecting two dissimilar anharmonic lattices exemplified by Fermi-Pasta-Ulam (FPU) model and Frenkel-kontorova (FK) model, we successfully build up one dimensional thermal diode. We find the rectifying effect is closely related to asymmetric interface thermal resistance (Kapitza resistance). And the asymmetric thermal resistance depends on how the temperature gradient is applied. Moreover, a qualitative relationship between the thermal rectification and the phonon spectra is proposed.

A Micromechanics Model for the Thermal Conductivity of Nanotube-Polymer Nanocomposites

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Gary D. Seidel ◽  
Dimitris C. Lagoudas
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Polymer Nanocomposites ◽  
Interphase Layer ◽  
Interfacial Thermal Resistance ◽  
Kapitza Resistance ◽  
End Effects ◽  
The Impact

A micromechanics approach for assessing the impact of an interfacial thermal resistance, also known as the Kapitza resistance, on the effective thermal conductivity of carbon nanotube-polymer nanocomposites is applied, which includes both the effects of the presence of the hollow region of the carbon nanotube (CNT) and the effects of the interactions amongst the various orientations of CNTs in a random distribution. The interfacial thermal resistance is a nanoscale effect introduced in the form of an interphase layer between the CNT and the polymer matrix in a nanoscale composite cylinder representative volume element to account for the thermal resistance in the radial direction along the length of the nanotube. The end effects of the interfacial thermal resistance are accounted for in a similar manner through the use of an interphase layer between the polymer and the CNT ends. Resulting micromechanics predictions for the effective thermal conductivity of polymer nanocomposites with randomly oriented CNTs, which incorporate input from molecular dynamics for the interfacial thermal resistance, demonstrate the importance of including the hollow region in addition to the interfacial thermal resistance, and compare well with experimental data.

Thermal Conductivity of Suspensions Based on Core–Shell Particles

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
G. I. Sukhinin ◽  
M. A. Serebryakova ◽  
S. A. Novopashin
Keyword(s):  
Thermal Conductivity ◽  
Analytical Solution ◽  
Thermal Resistance ◽  
Thermal Conduction ◽  
Interfacial Thermal Resistance ◽  
Core Shell ◽  
Kapitza Resistance ◽  
First Case ◽  
Shell Particles

An analytical solution of the problem of the thermal conductivity of a suspension containing core–shell particles was found. Solutions were found under the thickness of the shell tending to zero while the thermal conductivity of the shell was tending to zero and infinity. In the first case, the solution is shown to be equivalent to the solution that takes into account Kapitza interfacial thermal resistance. The role of contact Kapitza resistance in the processes of the thermal conduction of nanofluids is discussed.

Measurement of the Displacement Across a Coincidence Grain Boundary

1977 ◽  
Vol 35 ◽  
pp. 124-125
Author(s):  
J. W. Matthews ◽  
W. M. Stobbs
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stacking Fault ◽  
The Other ◽  
Measuring Technique ◽  
High Angle ◽  
Twin Boundaries ◽  
Rigid Displacement ◽  
Cubic Crystals ◽  
Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

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