Spectral attributes of sub-amorphous thermal conductivity in cross-linked organic–inorganic hybrids

Nanoscale ◽  
2020 ◽  
Vol 12 (25) ◽  
pp. 13491-13500
Author(s):  
Ali Morshedifard ◽  
Amir Moshiri ◽  
Konrad J. Krakowiak ◽  
Mohammad Javad Abdolhosseini Qomi
Keyword(s):  
Thermal Conductivity ◽  
Localized Modes ◽  
Hybrid Sample

Comparison of thermal conductivity in hybrid and pristine inorganic models and the modal spectrum of each sample showing the approximately unchanged number of propagating modes and a significant number of added localized modes in the hybrid sample.

scholarly journals Intrinsic Localized Lattice Modes and Thermal Transport: Potential Application in a Thermal Rectifier

2009 ◽  
Vol 1172 ◽  
Author(s):  
Michael E Manley
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Thermal Transport ◽  
Potential Application ◽  
Lattice Dynamics ◽  
Localized Modes ◽  
Uranium Metal ◽  
Intrinsic Localized Modes ◽  
Lattice Modes ◽  
Transport Potential

AbstractRecent experiments provide evidence of intrinsic localized modes (ILMs) in the lattice dynamics of conventional 3D materials. Here evidence that ILMs in uranium metal enhance the thermal conductivity is presented along with speculation on how thermal transport by ILMs might be used to improve a reported design for a solid-state thermal rectifier.

Role of Collective and Localized Modes on the Temperature-Dependent Thermal Conductivity in Polycrystalline C60 Fullerite Compacts

1997 ◽  
Vol 11 (23) ◽  
pp. 1031-1035 ◽  
Author(s):  
S. P. Tewari ◽  
Poonam Silotia ◽  
Kakoli Bera
Keyword(s):  
Thermal Conductivity ◽  
Relaxation Times ◽  
Collective Modes ◽  
Total Thermal Conductivity ◽  
Phonon Modes ◽  
Temperature Dependent ◽  
Localized Modes ◽  
Diffusive Modes ◽  
Temperature Dependent Thermal Conductivity

Recently observed thermal conductivity of polycrystalline C 60 fullerite compacts has been explained on the basis of a suggested dynamical model of the fullerites which takes into account the collective acoustic phonon modes with frequency dependent relaxation time and localized libronic and orientational diffusive modes with constant relaxation times, in the temperature range 0.7–300 K. Though the bulk of the conduction is via collective modes, the localized modes, too, contribute significantly to the total thermal conductivity.

scholarly journals Normal Mode Analysis of The Thermal conductivity in Amorphous Polymers: The Importance of Localized Modes

2021 ◽  
Author(s):  
Buxuan Li ◽  
Freddy DeAngelis ◽  
Gang Chen ◽  
Asegun Henry
Keyword(s):  
Thermal Conductivity ◽  
Normal Mode ◽  
Electrostatic Interactions ◽  
Normal Mode Analysis ◽  
Large Population ◽  
Amorphous Polymers ◽  
Inorganic Materials ◽  
Mode Analysis ◽  
Localized Modes ◽  
Covalent Bonds

Abstract Polymers are a unique class of materials from the perspective of normal mode analysis. Polymers consist of individual chains with repeating units and strong intra-chain covalent bonds, and amorphous arrangements among chains with weak inter-chain van der Waals and for some polymers also electrostatic interactions. Intuitively, this strong heterogeneity in bond strength can give rise to interesting features in the constituent phonons, but such effects have not been studied deeply before. Here, we use lattice dynamics and molecular dynamics to perform modal analysis of the thermal conductivity in amorphous polymers for the first time. We find an abnormally large population of localized modes in amorphous polymers, which is dramatically different from amorphous inorganic materials. Contrary to the common picture of thermal transport, localized modes in amorphous polymers are found to be the dominant contributors to thermal conductivity. We find that a significant portion of the localization happens within individual chains, but heat is dominantly conducted when localized modes involve two chains. These results suggest that even though each polymer is different, localized modes play a key role. The results provide new perspective on why polymer thermal conductivity is generally quite low and gives insight into how to potentially change it.

HARDNESS AND THERMAL CONDUCTIVITY OF As-Se-Te CHALCOGENIDE GLASSES

1981 ◽  
Vol 42 (C4) ◽  
pp. C4-931-C4-934 ◽  
Author(s):  
M. F. Kotkata ◽  
M.B. El-den
Keyword(s):  
Thermal Conductivity ◽  
Chalcogenide Glasses
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