Physical properties of chalcopyrite-type Cu1−xAgxGaTe2 by first-principles study

2016 ◽  
Vol 30 (30) ◽  
pp. 1650373 ◽  
Author(s):  
Li Xue ◽  
Yi-Ming Ren ◽  
Zheng-Long Hu
Keyword(s):  
Thermal Conductivity ◽  
Elastic Constants ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Lattice Parameter ◽  
Functional Theory ◽  
Lattice Volume ◽  
Te Material ◽  
Ag Substitution ◽  
Good Agreement

[Formula: see text] is a promising thermoelectric (TE) material for high temperature TE applications. This work systematically investigated the structural, elastic and thermodynamic properties of [Formula: see text] ([Formula: see text] = 0, 0.25, 0.5, 0.75 and 1) by density functional theory. The calculated lattice volume is expanded with the increase of Ag content, but this expansion is anisotropic. The lattice parameter along [Formula: see text]-axis is linear expansion, and along [Formula: see text]-axis is parabolic expansion, which is in good agreement with available experimental data. The phase stability of [Formula: see text] alloy is studied by analyzing the formation energy, cohesive energy and elastic constants. Shear modulus, Young’s modulus, sound velocities, Debye temperature and the minimum thermal conductivity are obtained from the calculated elastic constants. The results show that Ag substitution could reduce the lattice thermal conductivity, which is helpful for improving the TE properties of [Formula: see text].

scholarly journals Elastic Properties of Orthorhombic YBa2Cu3O7 under Pressure

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 497 ◽  
Author(s):  
Cai Chen ◽  
Lili Liu ◽  
Yufeng Wen ◽  
Youchang Jiang ◽  
Liwan Chen
Keyword(s):  
Thermal Conductivity ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Elastic Stability ◽  
Functional Theory ◽  
Conductivity Increase ◽  
Isotropic Pressure ◽  
The Density Functional Theory

The pressure dependence of the lattice and elastic constants of the orthorhombic YBa 2 Cu 3 O 7 are firstly investigated using the first principles calculations based on the density functional theory. The calculated lattice parameters at 0 GPa are in agreement with the available experimental data. By the elastic stability criteria under isotropic pressure, it is predicted that YBa 2 Cu 3 O 7 with and orthorhombic structure is mechanically stable under pressure up to 100 GPa. On the basis of the elastic constants, Pugh’s modulus ratio, Poisson’s ratio, elastic anisotropy, Debye temperature, and the minimum thermal conductivity of YBa 2 Cu 3 O 7 under pressure up to 100 GPa are further investigated. It is found that its ductility, Debye temperature, and minimum thermal conductivity increase with pressure.

scholarly journals Ultralow and anisotropic thermal conductivity in semiconductor As2Se3

2018 ◽  
Vol 20 (3) ◽  
pp. 1809-1816 ◽  
Author(s):  
Robert L. González-Romero ◽  
Alex Antonelli ◽  
Anderson S. Chaves ◽  
Juan J. Meléndez
Keyword(s):  
Thermal Conductivity ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Boltzmann Transport Equation ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Anisotropic Thermal Conductivity

An ultralow lattice thermal conductivity of 0.14 W m−1 K−1 along the b⃑ axis of As2Se3 single crystals was obtained at 300 K by first-principles calculations involving density functional theory and the resolution of the Boltzmann transport equation.

Ultra low lattice thermal conductivity and high carrier mobility of monolayer SnS2and SnSe2: a first principles study

2017 ◽  
Vol 19 (31) ◽  
pp. 20677-20683 ◽  
Author(s):  
Aamir Shafique ◽  
Abdus Samad ◽  
Young-Han Shin
Keyword(s):  
Thermal Conductivity ◽  
Density Functional Theory ◽  
First Principles ◽  
Carrier Mobility ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Functional Theory ◽  
First Principles Study ◽  
High Carrier Mobility ◽  
High Carrier

Using density functional theory, we systematically investigate the lattice thermal conductivity and carrier mobility of monolayer SnX2(X = S, Se).

Thermoelectric performance of XI2 (X = Ge, Sn, Pb) bilayers

2021 ◽  
Author(s):  
Nan Lu ◽  
Jie Guan
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
Dimensionless Figure Of Merit ◽  
Structure Calculations

Abstract We study the thermal and electronic transport properties as well as the TE performance of three two-dimensional XI2 (X = Ge, Sn, Pb) bilayers using density functional theory and Boltzmann transport theory. We compared the lattice thermal conductivity, electrical conductivity, Seebeck coefficient, and dimensionless figure of merit (ZT) for the XI2 monolayers and bilayers. Our results show that the lattice thermal conductivity at room temperature for the bilayers is as low as ~1.1-1.7 Wm-1K-1, which is about 1.6 times as large as the monolayers for all the three materials. Electronic structure calculations show that all the XI2 bilayers are indirect-gap semiconductors with the band gap values between 1.84 eV and 1.96 eV at PBE level, which is similar as the corresponding monolayers. The calculated results of ZT show that the bilayer structures display much less direction dependent TE efficiency and have much larger n-type ZT values compared with the monolayers. The dramatic difference between the monolayer and bilayer indicates that the inter-layer interaction plays an important role in the TE performance of XI2, which provides the tunability on their TE characteristics.

First-Principles Calculation of Elastic Constants for FeP

2013 ◽  
Vol 321-324 ◽  
pp. 1761-1765 ◽  
Author(s):  
Jian Ying Li ◽  
Jing Zhang ◽  
Qi Zhi Cao ◽  
Yi Fang Ouyang
Keyword(s):  
Elastic Constants ◽  
Density Functional ◽  
Formation Enthalpy ◽  
Density Functional Theory Method ◽  
First Principles Calculation ◽  
Electronic Density ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Theoretical Results ◽  
Good Agreement

The elastic constants of FeP with orthorhombic structure were calculated by using the density-functional theory method. The formation enthalpy, electronic density of states, bulk modulus, and lattice parameters of orthorhombic FeP were also calculated. All of the results are in good agreement with the experimental data and theoretical results available. The results indicate that orthorhombic FeP intermetallic compound is brittleness.

A first-principles studies on TlX (X=P, As)

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Yasemin Ciftci ◽  
Kemal Colakoglu ◽  
Engin Deligoz
Keyword(s):  
Thermodynamic Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Lattice Parameter ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Pseudopotential Approach ◽  
Theoretical Results ◽  
Good Agreement

AbstractWe present an ab initio study of the structural, electronic and thermodynamic properties of TlX(X=P,As). The plane-wave pseudopotential approach to the density-functional theory within the LDA and GGA approximations implemented in VASP (Viena Ab-initio Simulation Package) is used. The calculated lattice parameter, elastic constants, and band structures are compared with other available theoretical results, and good agreement is obtained. In addition, we have calculated the transition pressure (P t) from zinc-blende (ZB) to (rock-salt) NaCl structures, and have examined some thermodynamic properties.

Structural and mechanical properties of ternary MgCaSi phase: A study by density functional theory

2019 ◽  
Vol 44 (1-2) ◽  
pp. 50-59
Author(s):  
Rui Wu ◽  
Ya-Ping Wang ◽  
Yan Yang ◽  
Dong-Ming Luo ◽  
Hong Meng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Density Functional Theory ◽  
Elastic Constants ◽  
Electronic Structures ◽  
Density Functional ◽  
Ternary Phase ◽  
Functional Theory ◽  
Young’S Moduli ◽  
Cauchy Pressure

The structural, elastic, and electronic properties of multi-performance ternary phase MgCaSi have been investigated by density functional theory. The present results show that MgCaSi is thermodynamically and mechanically stable. The derived elastic constants indicate that the c axis is the easiest to compress, followed by the a and b axes. The bulk, shear, and Young’s moduli of MgCaSi are higher than these of the mother phase Ca2Si, demonstrating that the hardness of MgCaSi has been favorably improved. The higher Debye temperature of MgCaSi also indicates stronger interatomic interactions and better thermal conductivity. Although MgCaSi exhibits less brittleness based on Pugh’s empirical formula, Poisson’s ratio, and the Cauchy pressure, orthorhombic MgCaSi possesses lower anisotropy than Ca2Si based on several criteria. To reveal the bonding nature of MgCaSi, the electronic structures are further investigated. It is found that the strong Si−Si bond plays a significant role for structural stability and elastic properties.

Structure of Cu6PbO8

2000 ◽  
Vol 56 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Björn Winkler ◽  
Michael Chall ◽  
Chris J. Pickard ◽  
Victor Milman ◽  
Jim White
Keyword(s):  
Density Functional ◽  
Structural Parameters ◽  
Ambient Pressure ◽  
Lattice Parameter ◽  
Functional Theory ◽  
Close Packed Structure ◽  
Packed Structure ◽  
The Stability ◽  
Parameter Density ◽  
Good Agreement

First-principles quantum mechanical calculations based on density functional theory were performed for Cu_6PbO_8, hexacopper lead octaoxide, murdochite. The computed lattice parameter, density and bond lengths at ambient pressure are in good agreement with experimental data for murdochite. At about 18 GPa a phase transition is predicted, when a polymorph with a Suzuki-type structure, i.e. a close-packed structure with ordered vacancies, is proposed to become stable. The pressure dependence of the structural parameters has been calculated for the two polymorphs and their bulk moduli have been predicted. It is argued that the incorporation of halogen atoms is not a precondition for the stability of murdochite.

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