Abnormally Strong Electron–Phonon Scattering Induced Unprecedented Reduction in Lattice Thermal Conductivity of Two-Dimensional Nb2C

2019 ◽  
Vol 141 (21) ◽  
pp. 8503-8508 ◽  
Author(s):  
Yongda Huang ◽  
Jian Zhou ◽  
Guanjie Wang ◽  
Zhimei Sun
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Two Dimensional ◽  
Strong Electron ◽  
Electron Phonon Scattering

Effect of Parameters on Lattice Thermal Conductivity in Germanium Nanowires

2013 ◽  
Vol 832 ◽  
pp. 33-38 ◽  
Author(s):  
S.M. Mamand ◽  
M.S. Omar
Keyword(s):  
Thermal Conductivity ◽  
Low Temperatures ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Intrinsic Properties ◽  
Phonon Confinement ◽  
Germanium Nanowires ◽  
Transverse Modes ◽  
Experimental Values ◽  
Electron Phonon Scattering

Modified Callaway's theory was used to calculate lattice thermal conductivity (LTC) of Germanium nanowires. Results are compared to those of experimental values of the temperature dependence of LTC for nanowire diameters of 62, 19, and 15nm. In this calculation, both longitudinal and transverse modes are taken into account. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Effect of parameters, phonon confinement and imperfections in limiting thermal conductivity for the nanowires under considerations are investigated. The suppression in thermal conductivity of these nanowires is arise from electron-phonon scattering and phonon-boundary scattering at low temperatures, while at high temperatures is due to imperfections and intrinsic properties.

Nanostructured Thermoelectric Skutterudite Co1−xNixSb3 Alloys

2008 ◽  
Vol 8 (8) ◽  
pp. 4003-4006 ◽  
Author(s):  
Qinyu He ◽  
Qing Hao ◽  
Xiaowei Wang ◽  
Jian Yang ◽  
Yucheng Lan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundary ◽  
Direct Current ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Hot Press ◽  
Ni Doping ◽  
Strong Electron ◽  
Dimensionless Figure Of Merit ◽  
Electron Phonon Scattering

Nanostructured Ni-doped skutterudites Co1−xNixSb3 (with x ranging from 0.01 to 0.09) were prepared by ball milling and direct-current induced hot press. It was found that the thermal conductivity was reduced due to strong electron–phonon scattering from Ni-doping as well as phonon scattering from the increased grain boundary of the nanostructures. A maximum dimensionless figure-of-merit of 0.7 was obtained in Co0.91Ni0.09Sb3 at 525 °C.

Electron–phonon scattering effect on the lattice thermal conductivity of silicon nanostructures

2017 ◽  
Vol 19 (42) ◽  
pp. 28517-28526 ◽  
Author(s):  
Bo Fu ◽  
Guihua Tang ◽  
Yifei Li
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Thermal Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Silicon Nanostructures ◽  
Nanoscale Thermal Transport ◽  
Scattering Effect ◽  
Solid Thin Films ◽  
Electron Phonon Scattering

The effect of electron–phonon scattering on the nanoscale thermal transport is investigated systematically in nanowires, solid thin films and nanoporous thin films by considering the phonon–phonon, phonon–boundary and electron–phonon scattering simultaneously.

Lattice Thermal Conductivity Modelling of a Diatomic Nanoscale Material

2020 ◽  
Vol 10 (5) ◽  
pp. 602-609
Author(s):  
Adil H. Awad
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Correction Term ◽  
Nanoscale Material ◽  
New Approach ◽  
Two Samples ◽  
Conductivity Modelling ◽  
Callaway Model

Introduction: A new approach for expressing the lattice thermal conductivity of diatomic nanoscale materials is developed. Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries, point defects and other phonons via normal and Umklapp processes. Methods: A comparative study of the results of the present analysis and those obtained using Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering relaxation rate. The formulas derived from the correction term are also presented, and their difference from Callaway model is evident. Furthermore their percentage contribution is sufficiently small to be neglected in calculating lattice thermal conductivity. Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity with that of the experimental observation.

scholarly journals First-principles predictions of low lattice thermal conductivity and high thermoelectric performance of AZnSb (A = Rb, Cs)

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15486-15496
Author(s):  
Enamul Haque
Keyword(s):  
Thermal Conductivity ◽  
Debye Temperature ◽  
Layered Structure ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Performance

The layered structure, and presence of heavier elements Rb/Cs and Sb induce high anharmonicity, low Debye temperature, intense phonon scattering, and hence, low lattice thermal conductivity.

Theory of Thermal Conductivity of Micro- and Nano-structured Materials

2009 ◽  
Vol 1172 ◽  
Author(s):  
Gyaneshwar P. Srivastava
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Polycrystalline Diamond ◽  
Comprehensive Treatment ◽  
Si Nanowires ◽  
Quantitative Investigation ◽  
Debye Relaxation ◽  
Structured Materials ◽  
20 Nm

AbstractWe provide a brief discussion of the Boltzmann equation derived Callaway-Debye relaxation time theory of lattice thermal conductivity of micro- and nano-structured materials (of size greater than 20 nm. Incorporated in the theory is a comprehensive treatment of three-phonon scattering events. Using numerical results from this theory, we present a quantitative investigation of the magnitude and temperature variation of the conductivity of CVD polycrystalline diamond films, suspended GaAs nanostructures, Si nanowires, and AlN micro- and nano-ceramics.

Electron–phonon interaction in P-, As-, and Sb-doped germanium in the intermediate concentration region

1980 ◽  
Vol 58 (9) ◽  
pp. 1268-1274 ◽  
Author(s):  
V. Radhakrishnan ◽  
P. C. Sharma
Keyword(s):  
Thermal Conductivity ◽  
Conduction Band ◽  
Phonon Scattering ◽  
Metallic State ◽  
Deformation Potential ◽  
Concentration Region ◽  
Electron Phonon Interaction ◽  
Impurity Atoms ◽  
Intermediate Concentration ◽  
Electron Phonon Scattering

The electron–phonon scattering, in the analysis of low temperature thermal conductivity of n-type germanium, is studied in the intermediate donor concentration region. At low concentrations, below metal–insulator transition, the donor electrons are bound to the impurity atoms, and at high concentrations they are free in conduction band. The properties in the intermediate concentration are explained by Mikoshiba's "inhomogeneity model". According to this model, the electrons are in a mixed state both in non-metallic and metallic state. The electron concentrations in the non-metallic and metallic regions are calculated for each sample and the theory of both bound electron–phonon scattering and free electron–phonon scattering are applied. This theory of mixed electron–phonon scattering explains the thermal conductivity results of P-, As-, and Sb-doped germanium samples between 1 and 20 K for intermediate donor concentrations from 1.1 × 1017 to 5.6 × 1017 cm−3. The values of density-of-states effective mass are kept constant (= 0.22) without variation with temperature. The values of shear and dilatation-deformation potential constants are obtained from our calculations. The values of shear-deformation potential for the electrons in the bound region are found to be between 14 and 16 eV, while the values of dilatation-deformation potential are between 1 and 3.5 eV for the electrons in the conduction band and these values are in agreement with the experimentally measured values.

Anomalous in-plane lattice thermal conductivity in an atomically thin two-dimensional α-GeTe layer

2020 ◽  
Vol 22 (21) ◽  
pp. 12273-12280 ◽  
Author(s):  
Brahim Marfoua ◽  
Young Soo Lim ◽  
Jisang Hong
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
2D Materials ◽  
Two Dimensional ◽  
Plane Lattice

The bilayer α-GeTe displayed an exceptionally low lattice thermal conductivity never reported in the atomically thin 2D materials.

scholarly journals Electrical Transport and Thermoelectric Properties of SnSe–SnTe Solid Solution

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3854 ◽  
Author(s):  
Jun-Young Cho ◽  
Muhammad Siyar ◽  
Woo Chan Jin ◽  
Euyheon Hwang ◽  
Seung-Hwan Bae ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Single Crystal ◽  
Carrier Concentration ◽  
Electrical Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Practical Applications ◽  
Defect Sites

SnSe is considered as a promising thermoelectric (TE) material since the discovery of the record figure of merit (ZT) of 2.6 at 926 K in single crystal SnSe. It is, however, difficult to use single crystal SnSe for practical applications due to the poor mechanical properties and the difficulty and cost of fabricating a single crystal. It is highly desirable to improve the properties of polycrystalline SnSe whose TE properties are still not near to that of single crystal SnSe. In this study, in order to control the TE properties of polycrystalline SnSe, polycrystalline SnSe–SnTe solid solutions were fabricated, and the effect of the solid solution on the electrical transport and TE properties was investigated. The SnSe1−xTex samples were fabricated using mechanical alloying and spark plasma sintering. X-ray diffraction (XRD) analyses revealed that the solubility limit of Te in SnSe1−xTex is somewhere between x = 0.3 and 0.5. With increasing Te content, the electrical conductivity was increased due to the increase of carrier concentration, while the lattice thermal conductivity was suppressed by the increased amount of phonon scattering. The change of carrier concentration and electrical conductivity is explained using the measured band gap energy and the calculated band structure. The change of thermal conductivity is explained using the change of lattice thermal conductivity from the increased amount of phonon scattering at the point defect sites. A ZT of ~0.78 was obtained at 823 K from SnSe0.7Te0.3, which is an ~11% improvement compared to that of SnSe.

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