scholarly journals Analysis of the Effect of Resonant Phonon Scattering on the Thermal Conductivity of CaF2

1976 ◽  
Vol 29 (2) ◽  
pp. 19 ◽  
Author(s):  
PRW Hudson ◽  
EE Gibbs
Keyword(s):  
Thermal Conductivity ◽  
Low Temperatures ◽  
Phonon Scattering ◽  
Low Frequency ◽  
Resonant Scattering ◽  
Boundary Scattering ◽  
Scattering Mechanism ◽  
Scattering Mechanisms ◽  
Phonon Conduction

An analysis is presented of the various phonon contributions to the thermal conductivity of CaF2 doped with 1�0% and 0�1 % of yttrium or thulium. The broad phonon resonant scattering term is found to reduce the low frequency phonon conduction significantly. This is responsible for the relatively stronger suppression of the conductivity at low temperatures in the phonon boundary scattering region. Thus broad quasilocalized phonon resonant scattering mechanisms have a similar effect to phonon precipitate scattering. It also follows that, in the case of a broad resonant scattering mechanism, a dip will not necessarily be seen in the conductivity.

LATTICE THERMAL CONDUCTIVITY IN A HOLLOW SILICON NANOWIRE

2005 ◽  
Vol 19 (06) ◽  
pp. 1017-1027 ◽  
Author(s):  
WEI-QING HUANG ◽  
KE-QIU CHEN ◽  
Z. SHUAI ◽  
LINGLING WANG ◽  
WANGYU HU
Keyword(s):  
Thermal Conductivity ◽  
Relaxation Time ◽  
Lattice Thermal Conductivity ◽  
Silicon Nanowire ◽  
Boundary Scattering ◽  
Phonon Confinement ◽  
Time Approximation ◽  
Si Nanowire ◽  
Scattering Mechanisms ◽  
Relaxation Time Approximation

We theoretically investigate the lattice thermal conductivity of a hollow Si nanowire under the relaxation time approximation. The results show that the thermal conductivity in such structure is decreased markedly below the bulk value due to phonon confinement and boundary scattering. The thermal conductivities under different scattering mechanisms are given, and it is found that the boundary scattering is dominant resistive process for the decrease of the thermal conductivity.

The phonon scattering mechanism and its effect on temperature dependent thermal and thermoelectric properties of the silver nanowire

2022 ◽  
Author(s):  
Gui-Cang He ◽  
Lina Shi ◽  
Yilei Hua ◽  
Xiao-Li Zhu
Keyword(s):  
Thermoelectric Properties ◽  
Phonon Scattering ◽  
Silver Nanowire ◽  
Scattering Mechanism ◽  
Temperature Dependent ◽  
Scattering Mechanisms ◽  
Phonon Structure

In this work, the electron-phonon, the phonon-phonon, and phonon structure scattering mechanisms and the effect on the thermal and thermoelectric properties of the silver nanowire (AgNW) are investigated in temperature...

Thermal conductivity and phonon scattering mechanisms in La#x2212;x#x2212;x#x2212;xMxCuO4

1996 ◽  
Vol 105 (3-4) ◽  
pp. 981-986 ◽  
Author(s):  
Hiroyuki Fujishiro ◽  
Manabu Ikebe ◽  
Masayuki Yagi ◽  
Kiminari Nakasato ◽  
Yuzo Shibazaki ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Scattering Mechanisms

Thermal Conductivity of Single-Crystal and Sintered RBa2Cu3O7 at low Temperatures

1987 ◽  
Vol 99 ◽  
Author(s):  
J. E. Graebner ◽  
L. F. Schneemeyer ◽  
R. J. Cava ◽  
J. V. Waszczak ◽  
E. A. Rietman
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Single Crystals ◽  
Free Path ◽  
Low Temperatures ◽  
Rayleigh Scattering ◽  
Resonant Scattering ◽  
Sintered Sample ◽  
Mean Free Path ◽  
Strong Scattering

ABSTRACTThe thermal conductivity k of micro-twinned single crystals of YBa2Cu3O7 and HoBa2Cu3O7 and a sintered sample of YBa2Cu3O7 has been measured for temperatures 0.03<T<5K. For the single crystals, k is small and varies as T1.8-1.9 This behavior resembles k for glassy insulators except for the lack of a plateau above IK. It is concluded that the thermal carriers are phonons with their mean free path limited by resonant scattering from tunneling entities, as in glasses. Suggestions for the location of tunneling systems are given. For the sinter, k is still smaller but does not follow a power law T-dependence. It is similar to other sintered ceramics with the same particle size, where the phonon mean free path is dominated by Rayleigh scattering from the particles. This strong scattering from the microstructure presumably masks the scattering from TS within each particle.

scholarly journals Термоэлектрические свойства полуметаллических и полупроводниковых фольг и нитей Bi-=SUB=-1-x-=/SUB=-Sb-=SUB=-x-=/SUB=-

2019 ◽  
Vol 53 (5) ◽  
pp. 664
Author(s):  
А. Николаева ◽  
Л. Конопко ◽  
И. Гергишан ◽  
К. Рогацкий ◽  
П. Стачовик ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Phonon Scattering ◽  
Surface States ◽  
Experimental Investigations ◽  
Quantum Size ◽  
Thermoelectric Energy ◽  
Conductive Surface ◽  
Order Of Magnitude

AbstractThe results of experimental investigations into the thermoelectric properties (electrical conductivity, thermoelectric power, and thermal conductivity) of microtextured foils and single-crystal wires based on semimetal and semiconductor Bi_1 –_ x Sb_ x alloys are presented in the temperature range of 4.2–300 K. It is found that the band gap Δ E in Bi–17 at % Sb wires increases with decreasing wire diameter d , which is a manifestation of the quantum-size effect. At low temperatures ( T < 50 K), in the wires with d < 400 nm, the electrical conductivity increases due to the significant contribution of highly conductive surface states characteristic of topological insulators. It is found for the first time that the thermal conductivity of semimetal Bi–3 at % Sb foils at low temperatures is two orders of magnitude lower, and that of semiconductor Bi–16 at % Sb foils one order of magnitude lower, than that in bulk samples of the corresponding composition due to significant phonon scattering at grain boundaries and surfaces. This effect leads to considerable enhancement of the thermoelectric figure-of-merit ZT and can be used in miniature low-temperature thermoelectric energy converters.

EFFECT OF EMBEDDING NANOPARTICLES ON THERMAL CONDUCTIVITY OF CRYSTALLINE SEMICONDUCTORS: PHONON SCATTERING MECHANISM

2009 ◽  
Vol 08 (06) ◽  
pp. 551-556 ◽  
Author(s):  
K. K. CHOUDHARY ◽  
D. PRASAD ◽  
K. JAYAKUMAR ◽  
DINESH VARSHNEY
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundaries ◽  
Lattice Thermal Conductivity ◽  
Present Model ◽  
Phonon Scattering ◽  
Scattering Mechanism ◽  
Temperature Dependent ◽  
Pure Crystal ◽  
Model Hamiltonian ◽  
Heat Carriers

We evolve a theoretical model for quantitative analysis of decrease in thermal conductivity (κ) by embedding ErAs nanoparticles in In0.53Ga0.47As crystalline semiconductors. The lattice thermal conductivity by incorporating the scattering of phonons with defects, grain boundaries, electrons, and phonons in the model Hamiltonian are evaluated. It is noticed that the ErAs nanoparticles provide an additional scattering mechanism for phonons. The embedding of ErAs nanoparticles in In0.53Ga0.47As crystalline semiconductors, the phonon scattering with point defects and grain boundaries become more efficient, which cause in the decrease of thermal conductivity up to half of its value of pure crystal. Conclusively, the temperature dependent of thermal conductivity is determined by competition among the several operating scattering mechanisms for the heat carriers. Numerical analysis of thermal conductivity from the present model shows similar results as those revealed from experiments.

Thermal Transport in Few-Quintuple Bi2Te3 Thin Films and Nanoribbons

2011 ◽  
Author(s):  
Bo Qiu ◽  
Xiulin Ruan
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Temperature Dependence ◽  
Thermal Transport ◽  
Room Temperature ◽  
Phonon Scattering ◽  
Md Simulations ◽  
Boundary Scattering ◽  
Nanoporous Films

In this work, thermal conductivity of perfect and nanoporous few-quintuple Bi2Te3 thin films as well as nanoribbons with perfect and zig-zag edges is investigated using molecular dynamics (MD) simulations with Green-Kubo method. We find minimum thermal conductivity of perfect Bi2Te3 thin films with three quintuple layers (QLs) at room temperature, and we believe it originates from the interplay between inter-quintuple coupling and phonon boundary scattering. Nanoporous films and nanoribbons are studied for additional phonon scattering channels in suppressing thermal conductivity. With 5% porosity in Bi2Te3 thin films, the thermal conductivity is found to decrease by a factor of 4–6, depending on temperature, comparing to perfect single QL. For nanoribbons, width and edge shape are found to strongly affect the temperature dependence as well as values of thermal conductivity.

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