scholarly journals Ab initio lattice thermal conductivity of bulk and thin-film α-Al2O3

2018 ◽  
Vol 8 (03) ◽  
pp. 1119-1123 ◽  
Author(s):  
Bonny Dongre ◽  
Jesús Carrete ◽  
Natalio Mingo ◽  
Georg K.H. Madsen
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Ab Initio ◽  
Lattice Thermal Conductivity ◽  
Α Al2o3 ◽  
Image Position

Abstract

Onset of size effects in lattice thermal conductivity and lifetime of low-frequency thermal phonons

2012 ◽  
Vol 1404 ◽  
Author(s):  
A.A. Maznev
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Size Effects ◽  
Lattice Thermal Conductivity ◽  
Low Frequency ◽  
Square Root ◽  
Relaxation Rates ◽  
Frequency Limit ◽  
Conductivity Of Thin Films ◽  
Closed Form Formula

ABSTRACTThe onset of size effects in phonon-mediated thermal transport along a thin film at temperatures comparable or greater than the Debye temperature is analyzed theoretically. Assuming a quadratic frequency dependence of phonon relaxation rates in the low-frequency limit, a simple closed-form formula for the reduction of the in-plane thermal conductivity of thin films is derived. The effect scales as the square root of the film thickness, which leads to the prediction of measurable size-effects even at “macroscopic” distances ~100 μm. However, this prediction needs to be corrected to account for the deviation from the ω−2 dependence of phonon lifetimes at sub-THz frequencies due to the transition from Landau-Rumer to Akhiezer mechanism of phonon dissipation.

scholarly journals Effect of the electropositive elements A = Sc, La, and Ce on the microscopic dynamics of AV2Al20

2014 ◽  
Vol 16 (48) ◽  
pp. 27119-27133 ◽  
Author(s):  
Michael Marek Koza ◽  
Andreas Leithe-Jasper ◽  
Erik Sischka ◽  
Walter Schnelle ◽  
Horst Borrmann ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Ab Initio ◽  
Ground State ◽  
Lattice Thermal Conductivity ◽  
Neutron Spectroscopy ◽  
Cage Compound ◽  
Ground State Properties ◽  
Phonon Renormalization ◽  
Microscopic Dynamics

Neutron spectroscopy andab initiocalculations indicate the apparent glass-like lattice thermal conductivityκlof the nano-cage compound ScV2Al20as an effect of phonon renormalization predetermined by the crystal’s ground state properties.

Multiple phase formation and its influence on lattice thermal conductivity in β-Zn4Sb3

2011 ◽  
Vol 26 (15) ◽  
pp. 1925-1932 ◽  
Author(s):  
Titus Dasgupta ◽  
Christian Stiewe ◽  
Lothar Boettcher ◽  
Ralf Hassdorf ◽  
Hao Yin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Formation ◽  
Lattice Thermal Conductivity ◽  
Multiple Phase ◽  
Image Position

Abstract

Cross-plane thermal conductivity temperature dependence for PbSnSe/PbSe thin film superlattice material from 100K to 300K

2013 ◽  
Vol 1456 ◽  
Author(s):  
James D. Jeffers ◽  
Leonard Olona ◽  
Zhihua Cai ◽  
Khosrow Namjou ◽  
Patrick J. McCann
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Quantum Wells ◽  
Temperature Dependence ◽  
Lattice Thermal Conductivity ◽  
Continuous Wave ◽  
Emission Spectra ◽  
Multiple Quantum ◽  
Element Analysis ◽  
Plane Lattice

ABSTRACTThe temperature dependence of cross-plane lattice thermal conductivity for thin film IV-VI semiconductors grown by molecular beam epitaxy was measured. Samples consisting of PbSe/PbSrSe multiple quantum wells (MQWs) on PbSe/PbSnSe superlattices (SLs) were grown with variations in SL layer thickness and the number of SL pairs. Localized lattice temperatures within the MQW layers were extracted from analysis of continuous wave photoluminescence (PL) emission spectra at heat sink temperatures between 100 K and 250 K. These data, finite element analysis, and electrical characterization were used to determine cross-plane lattice thermal conductivity of two different SL materials. A SL material with three different PbSe/PbSnSe thicknesses (1.2/1.2, 1.8/1.8, and 2.4/2.4 nm) exhibited a fairly constant lattice thermal conductivity from 1.2 to 1.3 W/mK as the sample was cooled from 250 K to 100 K. Another SL material with five different PbSe/PbSnSe thicknesses (0.5/0.5, 1.0/1.0, 1.6/1.6, 2.1/2.1, and 2.6/2.6 nm) exhibited very low lattice thermal conductivities from 0.46 to 0.47 W/mK 250 K to 100 K. These results are consistent with reflection of low energy heat transporting acoustic phonons within the SL material.

Novel IV-V-VI Semiconductors with Ultralow Lattice Thermal Conductivity

2021 ◽  
Author(s):  
Yu Gan ◽  
Yongda Huang ◽  
Naihua Miao ◽  
Jian Zhou ◽  
Zhimei Sun
Keyword(s):  
Thermal Conductivity ◽  
Ab Initio ◽  
Energy Management ◽  
Thermal Barrier Coatings ◽  
High Throughput ◽  
Thermal Energy ◽  
Thermoelectric Materials ◽  
Lattice Thermal Conductivity ◽  
Thermal Barrier ◽  
Barrier Coatings

Crystalline solids with ultralow thermal conductivity are paramount for the development of thermoelectric materials and thermal barrier coatings for efficient thermal energy management. Here, by high-throughput ab initio calculations, we...

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