Generalized Boltzmann transport theory for relaxational heat conduction

2021 ◽  
Vol 173 ◽  
pp. 121225
Author(s):  
Shu-Nan Li ◽  
Bing-Yang Cao
Keyword(s):  
Heat Conduction ◽  
Transport Theory ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory

scholarly journals Band degeneracy enhanced thermoelectric performance in layered oxyselenides by first-principles calculations

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ning Wang ◽  
Menglu Li ◽  
Haiyan Xiao ◽  
Zhibin Gao ◽  
Zijiang Liu ◽  
...  
Keyword(s):  
Density Functional ◽  
Transport Theory ◽  
Relaxation Times ◽  
Wide Band ◽  
Type Systems ◽  
Model Systems ◽  
Boltzmann Transport ◽  
Seebeck Coefficients ◽  
Boltzmann Transport Theory ◽  
P Type

AbstractBand degeneracy is effective in optimizing the power factors of thermoelectric (TE) materials by enhancing the Seebeck coefficients. In this study, we demonstrate this effect in model systems of layered oxyselenide family by the density functional theory (DFT) combined with semi-classical Boltzmann transport theory. TE transport performance of layered LaCuOSe and BiCuOSe are fully compared. The results show that due to the larger electrical conductivities caused by longer electron relaxation times, the n-type systems show better TE performance than p-type systems for both LaCuOSe and BiCuOSe. Besides, the conduction band degeneracy of LaCuOSe leads to a larger Seebeck coefficient and a higher optimal carrier concentration than n-type BiCuOSe, and thus a higher power factor. The optimal figure of merit (ZT) value of 1.46 for n-type LaCuOSe is 22% larger than that of 1.2 for n-type BiCuOSe. This study highlights the potential of wide band gap material LaCuOSe for highly efficient TE applications, and demonstrates that inducing band degeneracy by cations substitution is an effective way to enhance the TE performance of layered oxyselenides.

scholarly journals Realizing and Adjusting the Thermoelectric Application of MoO3 Monolayer via Oxygen Vacancies

2019 ◽  
Author(s):  
Wenwen Zheng ◽  
Wei Cao ◽  
Ziyu Wang ◽  
Huixiong Deng ◽  
Jing Shi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Oxygen Vacancies ◽  
Transport Theory ◽  
Electronic Conductivity ◽  
Boltzmann Transport ◽  
Anisotropic Behavior ◽  
Boltzmann Transport Theory ◽  
Thermoelectric Application

We have investigated the thermoelectric properties of MoO3 monolayer and its defective structures with oxygen vacancies by using first-principles method combined with Boltzmann transport theory. Our results show that the thermoelectric properties of MoO3 monolayer exhibit an anisotropic behavior which is caused by the similar anisotropic phenomenon of electronic conductivity and thermal conductivity. Moreover, the creation of oxygen vacancies proves to be an effective way to enhance the ZT values of MoO3 monolayer which is caused by the sharp peak near the Fermi level in density of states. The increased ZT value can reach 0.84 along x-axis at 300K.

Ab-initio study of mechanical and thermoelectric properties of topological semimetal: LaAuPb

2021 ◽  
Author(s):  
Megha Goyal ◽  
M.M. Sinha
Keyword(s):  
Thermoelectric Properties ◽  
Density Functional ◽  
Transport Theory ◽  
Poisson Ratio ◽  
Topological Phase ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
Material Fabrication ◽  
The Stability

Abstract Heusler compounds are a tuneable class of material with a cubic crystal structure that can serve as a platform to study the topological phase of a material. These materials have numerous technological and scientific applications. So, in the present work, the mechanical, thermodynamical, and thermoelectric properties of LaAuPb in the topological phase have been reported by using density functional theory and Boltzmann transport theory. LaAuPb is mechanically stable, and the Poisson ratio reveals its ductile nature. The specific heat of the proposed compound at room temperature is 73.94 J K-1 mol-1 at constant volume. Debye’s temperature is estimated to be 188.64K. Moreover, the lattice thermal conductivity of the compound is 14.64 W/mK and 3.66 W/mK at 300K and 1200K, respectively. Good thermoelectric response of LaAuPb can be confirmed by its high value of the figure of merit (0.46) at 1200K. Hence, it is a potential material for thermoelectric applications. This work will help future researchers to better understand the stability, nature and behaviour of LaAuPb in material fabrication.

The n- and p-type thermoelectric response of a semiconducting Co-based quaternary Heusler alloy: a density functional approach

2019 ◽  
Vol 7 (25) ◽  
pp. 7664-7671 ◽  
Author(s):  
Enamullah Enamullah ◽  
Pil-Ryung Cha
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Properties ◽  
Heusler Alloy ◽  
Density Functional ◽  
Transport Theory ◽  
Mechanical Stability ◽  
Functional Approach ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory ◽  
P Type

In the combined framework of density functional and Boltzmann transport theory, we have systematically studied the electronic structure, mechanical stability and thermoelectric properties of the semiconducting quaternary Heusler alloy, CoFeTiAl.

Band structure, phonon spectrum, and thermoelectric properties of β-BiAs and β-BiSb monolayers

2020 ◽  
Vol 8 (2) ◽  
pp. 581-590 ◽  
Author(s):  
C. Y. Wu ◽  
L. Sun ◽  
J. C. Han ◽  
H. R. Gong
Keyword(s):  
Band Structure ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Phonon Spectrum ◽  
Transport Theory ◽  
First Principles Calculation ◽  
Boltzmann Transport ◽  
Band Structures ◽  
Boltzmann Transport Theory ◽  
Phonon Spectra

First-principles calculation and Boltzmann transport theory have been combined to comparatively investigate the band structures, phonon spectra, and thermoelectric properties of both β-BiSb and β-BiAs monolayers.

scholarly journals Electronic, optical and thermoelectric properties of Fe2ZrP compound determined via first-principles calculations

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25900-25911 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Jaafar Jalilian ◽  
Mahnaz Mohammadi
Keyword(s):  
Density Functional Theory ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Transport Theory ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
The Density Functional Theory

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe2ZrP compound.

scholarly journals Pressure-induced enhancement in the thermoelectric properties of monolayer and bilayer SnSe 2

2018 ◽  
Vol 5 (3) ◽  
pp. 171827 ◽  
Author(s):  
Daifeng Zou ◽  
Chuanbin Yu ◽  
Yuhao Li ◽  
Yun Ou ◽  
Yongyi Gao
Keyword(s):  
Electronic Structure ◽  
Thermoelectric Properties ◽  
High Performance ◽  
Transport Theory ◽  
Strain Engineering ◽  
External Pressure ◽  
Van Der Waals Interactions ◽  
Valuable Insight ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory

The electronic structures of monolayer and bilayer SnSe 2 under pressure were investigated by using first-principles calculations including van der Waals interactions. For monolayer SnSe 2 , the variation of electronic structure under pressure is controlled by pressure-dependent lattice parameters. For bilayer SnSe 2 , the changes in electronic structure under pressure are dominated by intralayer and interlayer atomic interactions. The n -type thermoelectric properties of monolayer and bilayer SnSe 2 under pressure were calculated on the basis of the semi-classical Boltzmann transport theory. It was found that the electrical conductivity of monolayer and bilayer SnSe 2 can be enhanced under pressure, and such dependence can be attributed to the pressure-induced changes of the Se–Sn antibonding states in conduction band. Finally, the doping dependence of power factors of n -type monolayer and bilayer SnSe 2 at three different pressures were estimated, and the results unveiled that thermoelectric performance of n -type monolayer and bilayer SnSe 2 can be improved by applying external pressure. This study benefits to understand the nature of the transport properties for monolayer and bilayer SnSe 2 under pressure, and it offers valuable insight for designing high-performance thermoelectric few-layered SnSe 2 through strain engineering induced by external pressure.

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