scholarly journals Anisotropic intrinsic lattice thermal conductivity of phosphorene from first principles

2015 ◽  
Vol 17 (7) ◽  
pp. 4854-4858 ◽  
Author(s):  
Guangzhao Qin ◽  
Qing-Bo Yan ◽  
Zhenzhen Qin ◽  
Sheng-Ying Yue ◽  
Ming Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Free Path ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Mean Free Path

The intrinsic lattice thermal conductivity and the representative phonon mean free path of phosphorene.

Anisotropy in lattice thermal conductivity tensor of bulk hexagonal-MT2 (M = W, Mo and T = S and Se) by first principles phonon calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 7817-7828 ◽  
Author(s):  
Yingchun Ding ◽  
Min Chen ◽  
Bing Xiao
Keyword(s):  
Thermal Conductivity ◽  
Free Path ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Mean Free Path ◽  
Conductivity Tensor ◽  
Thermal Conductivity Tensor

Anisotropies in phonon mean free path and thermal conductivity as a function of temperature are calculated for 2H-MT2 structures.

scholarly journals First-Principles Study of Structure, Elastic Properties, and Thermal Conductivity of Monolayer Calcium Hydrobromide

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Si-Hua Li ◽  
Cui-E Hu ◽  
Xiao-Lu Wang ◽  
Yan Cheng
Keyword(s):  
Thermal Conductivity ◽  
Elastic Properties ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Mechanical Stability ◽  
Iterative Solution ◽  
Mean Free Path ◽  
Hydrogen Atmosphere ◽  
Theoretical Studies ◽  
Boltzmann Transport

In recent years, some laboratories have been able to prepare calcium hydrobromide (CaHBr) by melting hydride and anhydrous bromide or metal and bromide in a hydrogen atmosphere at 900°C and have studied some of its properties. But there are few theoretical studies, especially the theoretical studies of monolayer CaHBr. We use the first-principles method to calculate the structure, elastic properties, and lattice thermal conductivity of the monolayer CaHBr based on the Boltzmann transport equation. We obtain a stable crystal structure by the optimization of monolayer CaHBr. By calculating the elastic constant of monolayer CaHBr, its mechanical stability is proved, and the elastic limit of monolayer CaHBr is obtained by biaxial tensile strain on monolayer CaHBr. And the corresponding phonon spectra show no imaginary frequency, indicating the dynamic stability of the monolayer CaHBr. By the ShengBTE code, we calculate the lattice thermal conductivity of the monolayer CaHBr, the iterative solution of BTE and RTA at 300 K–1200 K is obtained, and the lattice thermal conductivity at room temperature is κ ι BTE = 2.469   W / m ⋅ K and κ ι RTA = 2.201   W / m ⋅ K , respectively. It can be seen that the lattice thermal conductivity of monolayer CaHBr is low. And by analyzing the phonon spectrum, the scattering rate, and the mean free path of the phonons, the lattice thermal conductivity of monolayer CaHBr mainly depends on the acoustic modes. We hope this study can provide theoretical guidance for the experiments and practical application of monolayer CaHBr.

Ioffe–Regel limit and lattice thermal conductivity reduction of high performance (AgSbTe2)15(GeTe)85 thermoelectric materials

2014 ◽  
Vol 2 (9) ◽  
pp. 3251-3256 ◽  
Author(s):  
Tiejun Zhu ◽  
Hongli Gao ◽  
Yi Chen ◽  
Xinbing Zhao
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Free Path ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Lattice Thermal Conductivity ◽  
State Of The Art ◽  
Mean Free Path ◽  
Lattice Parameter ◽  
Fine Grained

This work shows that the carrier mean free path of TAGS-85 thermoelectric materials is comparable to the lattice parameter, and that refining the grain size will not affect the mobility while benefiting the thermal conductivity reduction. A state-of-the-art ZT of ~ 1.6 is obtained for the fine-grained samples.

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.

scholarly journals Ballistic Heat Transport in Nanocomposite: The Role of the Shape and Interconnection of Nanoinclusions

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1982
Author(s):  
Paul Desmarchelier ◽  
Alice Carré ◽  
Konstantinos Termentzidis ◽  
Anne Tanguy
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Free Path ◽  
Mean Free Path ◽  
Strong Increase ◽  
Moderate Increase ◽  
Energy Propagation ◽  
The Mean ◽  
Dynamics Simulations

In this article, the effect on the vibrational and thermal properties of gradually interconnected nanoinclusions embedded in an amorphous silicon matrix is studied using molecular dynamics simulations. The nanoinclusion arrangement ranges from an aligned sphere array to an interconnected mesh of nanowires. Wave-packet simulations scanning different polarizations and frequencies reveal that the interconnection of the nanoinclusions at constant volume fraction induces a strong increase of the mean free path of high frequency phonons, but does not affect the energy diffusivity. The mean free path and energy diffusivity are then used to estimate the thermal conductivity, showing an enhancement of the effective thermal conductivity due to the existence of crystalline structural interconnections. This enhancement is dominated by the ballistic transport of phonons. Equilibrium molecular dynamics simulations confirm the tendency, although less markedly. This leads to the observation that coherent energy propagation with a moderate increase of the thermal conductivity is possible. These findings could be useful for energy harvesting applications, thermal management or for mechanical information processing.

Experiments on the flow of heat in liquid helium below 0.7 °K

1958 ◽  
Vol 246 (1246) ◽  
pp. 390-405 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Liquid Helium ◽  
Free Path ◽  
Empirical Relation ◽  
Mean Free Path ◽  
Series Of Experiments ◽  
The Mean ◽  
Set Up ◽  
Low Pressures ◽  
Measured Thermal Conductivity

A series of experiments has been performed to study the steady flow of heat in liquid helium in tubes of diameter 0.05 to 1.0 cm at temperatures between 0.25 and 0.7 °K. The results are interpreted in terms of the flow of a gas of phonons, in which the mean free path λ varies with temperature, and may be either greater or less than the diameter of the tube d . When λ ≫ d the flow is limited by the scattering of the phonons at the walls, and the effect of the surface has been studied, but when λ ≪ d viscous flow is set up in which the measured thermal conductivity is increased above that for wall scattering. This behaviour is very similar to that observed in the flow of gases at low pressures, and by applying kinetic theory to the problem it can be shown that the mean free path of the phonons characterizing viscosity can be expressed by the empirical relation λ = 3.8 x 10 -3 T -4.3 cm. This result is inconsistent with the temperature dependence of λ as T -9 predicted theoretically by Landau & Khalatnikov (1949).

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