Electronic Structure and Transport Properties of La2Zr2O7 Pyrochlore from First Principles

2018 ◽  
Vol 281 ◽  
pp. 767-773
Author(s):  
Zheng Li ◽  
Wei Pan
Keyword(s):  
Thermal Conductivity ◽  
Transport Properties ◽  
Electron Concentration ◽  
Boltzmann Transport ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Electronic Thermal Conductivity ◽  
Transport Calculation ◽  
Scattering Time ◽  
High Temperature Electronic

The first principle calculation as well as the Boltzmann transport calculation have been employed to study the high temperature electronic transport properties of pyrochlore La2Zr2O7. Combing constant scattering time approximation and experiment data, the electronic thermal conductivity and electron concentration are calculated as a function of temperature. The electronic thermal conductivity is 2.6×10-4 W/(m.s) at 1270K and 7.2×10-3 W/(m.s) at 1770K. The electron concentration increase rapidly with when the temperature is above 1600K.

Computational Revolutions in Lattice Thermal Conductivity

2021 ◽  
Vol 324 ◽  
pp. 181-187
Author(s):  
Lahiruni Isurika Ranasinghe ◽  
Chung Hao Hsu
Keyword(s):  
Thermal Conductivity ◽  
Lattice Dynamics ◽  
Lattice Thermal Conductivity ◽  
Computational Approach ◽  
Semiconductor Materials ◽  
First Principle ◽  
Boltzmann Transport ◽  
Semiconducting Materials ◽  
Principle Calculation ◽  
First Principle Calculation

Understanding and controlling the phonon, the dominant heat carrier of semiconductor materials, is essential to developing a wide variety of applications. This article studies the theoretical and computational approach of the calculation of lattice thermal conductivity of semiconducting materials. Despite having different methods to calculate the lattice thermal conductivity, first-principle estimates predict more accurately in most applications. This motivates to present the descriptive explanation on first-principle calculation with the combination of lattice dynamics and Boltzmann transport equation. Finally, we summarized an overview of the recent achievements and opportunities.

Band Structures and Transport Properties of Half-Heusler Compounds NbMSb (M = Fe, Ru)

2016 ◽  
Vol 847 ◽  
pp. 171-176
Author(s):  
Teng Fang ◽  
Shu Qi Zheng ◽  
Hong Chen ◽  
Peng Zhang
Keyword(s):  
Transport Properties ◽  
Valence Band Maximum ◽  
Thermoelectric Generators ◽  
Heusler Compounds ◽  
Boltzmann Transport ◽  
Band Structures ◽  
Seebeck Coefficients ◽  
Electrical Conductivities ◽  
Scattering Time ◽  
P Type

The band structures and transport properties of Half-Heusler compounds NbFeSb and NbRuSb were studied using ab initio calculations and the Boltzmann transport equation with constant scattering time approximation (CSTA). Both compounds were identified as good p-type thermoelectric materials because of the combination of heavy and light bands in the valence band maximum (VBM). The Seebeck coefficients for NbRuSb were lower than that for NbFeSb; while the electrical conductivities for NbRuSb were little higher than that for NbFeSb. Consequently, the power factors in the p-type regimes for both compounds were similar at a given temperature. NbFeSb and NbRuSb could be efficient materials for thermoelectric generators based on the results in the present investigation.

scholarly journals Lattice thermal conductivity of borophene from first principle calculation

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Huaping Xiao ◽  
Wei Cao ◽  
Tao Ouyang ◽  
Sumei Guo ◽  
Chaoyu He ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation

Effect of Al substitution on Thermoelectric Performance of CuInTe2 compounds

2015 ◽  
Vol 1735 ◽  
Author(s):  
Chuandeng Hu ◽  
Kunling Peng ◽  
Guiwen Wang ◽  
Lijie Guo ◽  
Guoyu Wang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Al Substitution ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Grain Surface

ABSTRACTThermoelectric CuIn1-xAlxTe2 compounds (x=0, 0.05, 0.1, 0.15, 0.50) have been synthesized by solid state reaction followed by spark plasma sintering. The influence of Al substitution on electrical and thermal transport properties has been investigated in the CuInTe2 compounds. It was found that the Seebeck coefficient and electrical conductivity is reduced by isovalent replacement of In with Al. Our first principle calculation indicates Al substitution leads to the widen band gap, the reduction in the number of degeneracy of valence band and the effective mass. Furthermore, a large reduction in thermal conductivity is achieved through the enhanced phonon scattering via point defect as well as the nano-sized particles observed between grain boundaries and on the grain surface. In spite of the reduced charge transport properties, an improved figure-of- merit ZT is achieved, reaching 0.8 at 800 K, 33% higher in comparison to the pure CuInTe2 compound.

scholarly journals Electronic Thermal Conductivity and Thermoelectric Performance of PbBi4Te7

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Tran Van Quang
Keyword(s):  
Thermal Conductivity ◽  
Carrier Concentration ◽  
Bismuth Telluride ◽  
Density Functional ◽  
Binary Compound ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
Relaxation Time Approximation ◽  
Electronic Thermal Conductivity ◽  
Constant Relaxation Time

Bismuth telluride and its related compounds are the state-of-the-art thermoelectric materials operating at room temperature. Bismuth telluride with Pb substituted, PbBi4Te7, has been found to be a new quasi-binary compound with an impressive high power factor. In this work, in the framework of density functional theory, we study the electronic thermal conductivity of the compound by employing the solution of Boltzmann Transport Equation in a constant relaxation-time approximation. The results show that the electronic thermal conductivity drastically increases with the increase of temperature and carrier concentration which have a detrimental effect on the thermoelectric performance. At a particular temperature, the competition between the thermal conductivity, the Seebeck coefficient and the electrical conductivity limits the thermoelectric figure of merit, ZT. The maximum ZT value of about 0.47 occurs at 520 K and at the carrier concentration of 5.0×1019cm-3 for n-type doping. This suggests that to maximize the thermoelectric performance of the compound, the carrier concentration must be carefully controlled and optimized whereas the best operating temperature is around 500 K.

scholarly journals Electronic structure and Thermoelectric Properties of Hybrid Organic-Inorganic Perovskites [NH3-(CH2)3-COOH]2CdCl4

2021 ◽  
Vol 22 (4) ◽  
pp. 750-755
Author(s):  
Elmustafa Ouaaka ◽  
Said Kassou ◽  
Mahmoud Ettakni ◽  
Salaheddine Sayouri ◽  
Ahmed Khmou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structure ◽  
Figure Of Merit ◽  
First Principle ◽  
Generalized Gradient ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Generalized Gradient Approximation ◽  
Thermoelectric Characteristic ◽  
Good Agreement

In this work, we conducted the first principle calculation of electronic structure and transport properties of [NH3-(CH2)3-COOH]2CdCl4 (Acid-Cd). The generalized gradient approximation is used in structural optimization and electronic structure. The theoretical band gap value found is in good agreement with experimental. Electronic thermal conductivity, electrical conductivity, Seebeck coefficient (S) and figure of merit (ZT) have been calculated using semi-local Boltzmann theory to predict the thermoelectric characteristic of the studied materials.

scholarly journals Computational Envision of Structural, Electronic, Mechanical and Thermoelectric Properties of PdXSn (X=Zr, Hf) half Heusler compounds

2022 ◽  
Author(s):  
Bindu Rani ◽  
Aadil Wani ◽  
Utkir Sharopov ◽  
Kulwinder Kaur ◽  
Shobhna Dhiman
Keyword(s):  
Band Gap ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
First Principle ◽  
Heusler Compounds ◽  
Boltzmann Transport ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Good Thermal Stability ◽  
Indirect Band Gap

Half heusler compounds have gained attention due to their excellent properties and good thermal stability. In this paper, using first principle calculation and Boltzmann transport equation, we have investigated structural, electronic, mechanical and thermoelectric properties of PdXSn (X=Zr,Hf) half Heusler materials. These materials are indirect band gap semiconductors with band gap of 0.52 (0.44) for PdZrSn (PdHfSn). Calculations of elastic and phonon characteristics show that both materials are mechanically and dynamically stable. At 300K the magnitude of lattice thermal conductivity observed for PdZrSn is 15.16 W/mK and 9.53 W/mK for PdHfSn. The highest ZT value for PdZrSn and PdHfSn is 0.32 and 0.4 respectively.

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