Limiting Value of Debye Temperature for Superconducting and Normal Indium from Low-Temperature Elastic Constants

1961 ◽  
Vol 6 (1) ◽  
pp. 3-4 ◽  
Author(s):  
B. S. Chandrasekhar ◽  
J. A. Rayne
Keyword(s):  
Low Temperature ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Limiting Value

scholarly journals The Room Temperature Elastic Constants of Caesium Thiocyanate

1983 ◽  
Vol 36 (1) ◽  
pp. 85 ◽  
Author(s):  
MA Irving ◽  
S Prawer ◽  
TF Smith ◽  
TR Finlayson
Keyword(s):  
Low Temperature ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Elastic Waves ◽  
Room Temperature ◽  
Elastic Stiffness ◽  
Orthorhombic Crystal ◽  
Propagation Of Elastic Waves ◽  
Limiting Value ◽  
Rigid Ion Model

The velocities of propagation of elastic waves in caesium thiocyanate have been measured along the three orthorhombic axes and normal to the (110), (011) and (101) planes using a double-transducer technique at 10 MHz. The velocities are found to be consistent with the orthorhombic crystal symmetry, and in favourable agreement with a recently published rigid-ion model calculation. The calculated elastic stiffness constants have values C11 = 18'9�0'7, C22 = 20�6�1�0, C33 = 28�1�1�6, C44 = 1'96�0'05, Css = 7�30�0�2, C66 = 3�04�0�07, C12 = 7'8�4'3, Cl3 = 14�8�4 and e23 = 6�3�4GPa. The calculated values for the adiabatic bulk modulus and the low temperature limiting value of the Debye temperature are 13�2 � 3�5 GPa and 132 K respectively

Study of thermo-elastic and lattice dynamics properties of half-Heusler compounds XMgAl (X = Li, Na) by computational investigations

2019 ◽  
Vol 33 (08) ◽  
pp. 1950093 ◽  
Author(s):  
A. Afaq ◽  
Abu Bakar ◽  
M. Rizwan ◽  
M. Aftab Fareed ◽  
H. Bushra Munir ◽  
...  
Keyword(s):  
Debye Temperature ◽  
Elastic Constants ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Dynamic Properties ◽  
Mechanical Parameters ◽  
Heusler Compounds ◽  
Generalized Gradient ◽  
Text Type ◽  
Quantum Espresso

In this study, thermo-elastic and lattice dynamic properties of XMgAl (X = Li, Na) half-Heusler compounds are investigated using density functional theory implemented in WIEN2k and Quantum ESPRESSO codes. Generalized gradient approximation (GGA) as an exchange correlation function has been used in Kohn–Sham equations. Firstly, the structure of these Heusler compounds is optimized and then these optimized parameters are used to find three elastic constants [Formula: see text], [Formula: see text] and [Formula: see text] for [Formula: see text] type structures. Three elastic constants are then used to determine different elastic moduli like bulk modulus, shear modulus, Young’s modulus and other mechanical parameters like Pugh’s ratio, Poisson’s ratio, anisotropic ratio, sound velocities, Debye temperature and melting temperature. On behalf of these mechanical parameters, the brittle/ductile nature and isotropic/anisotropic behavior of the materials has been studied. Different regions of vibrational modes in the materials are also discussed on behalf of Debye temperature calculations. The vibrational properties of the half-Heusler compounds are computed using Martins–Troullier pseudo potentials implemented in Quantum ESPRESSO. The phonon dispersion curves and phonon density of states in first Brillion zone are obtained and discussed. Reststrahlen band of LiMgAl is found greater than NaMgAl.

scholarly journals Pressure Effect on Elastic Constants and Related Properties of Ti3Al Intermetallic Compound: A First-Principles Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2015 ◽  
Author(s):  
Xianshi Zeng ◽  
Rufang Peng ◽  
Yanlin Yu ◽  
Zuofu Hu ◽  
Yufeng Wen ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Debye Temperature ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Theoretical Data ◽  
Young’S Moduli ◽  
Anisotropic Factor ◽  
Isotropic Pressure

Using first-principles calculations based on density functional theory, the elastic constants and some of the related physical quantities, such as the bulk, shear, and Young’s moduli, Poisson’s ratio, anisotropic factor, acoustic velocity, minimum thermal conductivity, and Debye temperature, are reported in this paper for the hexagonal intermetallic compound Ti 3 Al. The obtained results are well consistent with the available experimental and theoretical data. The effect of pressure on all studied parameters was investigated. By the mechanical stability criteria under isotropic pressure, it is predicted that the compound is mechanically unstable at pressures above 71.4 GPa. Its ductility, anisotropy, and Debye temperature are enhanced with pressure.

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.

Vibrational Spectrum, Caloric Curve, Low-Temperature Heat Capacity, and Debye Temperature of Sodium Clusters: The Na139+ Case

2013 ◽  
Vol 117 (21) ◽  
pp. 11393-11398 ◽  
Author(s):  
Huziel E. Sauceda ◽  
J. Jesús Pelayo ◽  
Fernando Salazar ◽  
Luis A. Pérez ◽  
Ignacio L. Garzón
Keyword(s):  
Heat Capacity ◽  
Low Temperature ◽  
Vibrational Spectrum ◽  
Debye Temperature ◽  
Sodium Clusters ◽  
Temperature Heat ◽  
Caloric Curve ◽  
Low Temperature Heat Capacity

scholarly journals Sound velocities and Debye temperature of BeSe under high pressure up to 50 GPa

2016 ◽  
Vol 5 (1) ◽  
pp. 7
Author(s):  
Salah Daoud
Keyword(s):  
High Pressure ◽  
Elastic Wave ◽  
Mechanical Behavior ◽  
Debye Temperature ◽  
Elastic Constants ◽  
Structural Parameters ◽  
Theoretical Data ◽  
Elastic Wave Velocity ◽  
Brittle Behavior ◽  
Sound Velocities

The mechanical behavior, sound velocities and Debye temperature of beryllium-selenide (BeSe) semiconductor under pressure up to 50 GPa have been estimated using the structural parameters and elastic constants of Fanjie Kong and Gang Jiang (Physica B 404 (2009) 3935-3940). The Pugh ratio, the directional dependence of elastic wave velocity, the longitudinal, transverse and average sound velocities, and the Debye temperature are successfully predicted and analyzed in comparison with the available theoretical data. The analysis of the Pugh ratio indicates that this compound is prone to brittle behavior. Our obtained results of the longitudinal, transverse and average sound velocities at high pressure indicate that these of Kong and Jiang (Physica B 404 (2009) 3935-3940) are not correctly predicted.

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