scholarly journals Electronic and thermal properties of LuNi2B2C under pressure

2020 ◽  
Vol 48 (5-6) ◽  
pp. 469-479
Author(s):  
LILI LIU ◽  
YUHAN JIANG ◽  
LIWAN CHEN ◽  
YOUCHANG JIANG ◽  
YELU HE ◽  
...  

The electronic and thermal properties of LuNi2B2C were studied by performing density-functional theory (DFT) and density functional perturbation theory (DFPT). No virtual frequencies appear on the phonon spectrum, indicating that LuNi2B2C is dynamically stable in the tetragonal structure up to 30 GPa. The density of states at Fermi energy EF is nonzero and falls on the sharp peak, which is why LuNi2B2C has a high superconducting temperature. Moreover, the temperature and pressure dependences of bulk modulus, heat capacity at constant pressure and thermal expansion coefficient in a wide temperature (0-900 K) and pressure (0-30 GPa) ranges are presented in this study.

2010 ◽  
Vol 650 ◽  
pp. 313-319 ◽  
Author(s):  
Dong Lin Li ◽  
Ping Chen ◽  
Jian Xiong Yi ◽  
Bi Yu Tang ◽  
Li Ming Peng ◽  
...  

Ab inito density functional theory (DFT) and density function perturbation theory (DFPT) have been applied to investigate the thermal properties of the face-center-cubic (fcc) Al3Zr alloy over a wide range of pressure and temperature. Phonon dispersions were obtained at equilibrium and strained configurations by density functional perturbation theory. Using the quasiharmonic approximation for the free energy, several interesting physical quantities such as thermal Grüneisen parameter, heat capacity at constant pressure and volume, thermal expansion coefficient and entropy, as well as adiabatic bulk modulus and isothermal bulk modulus, were calculated as a function of temperature and pressure, and the variation features of these quantities were discussed in details.


2012 ◽  
Vol 534 ◽  
pp. 192-196
Author(s):  
Yu Hong Huang ◽  
Wan Qi Jie ◽  
Gang Qiang Zha

The elastic and thermodynamic properties of CdTe are studied under a pressure up to 8GPa and at a temperature range of 0~900K, by density functional theory as well as quasi-harmonic Debye model. The calculated bulk modulus B and its derivative B' are consistent with the values fitted according to Debye model, which confirms the applicability of Debye model to CdTe. Heat capacity Cv , Grüneisen parameter and thermal expansion coefficient decrease with pressure, but increase with temperature. It is an opposite case for Debye temperature . The results may be instructive for CdTe to be applied in extreme conditions.


2015 ◽  
Vol 44 (28) ◽  
pp. 12735-12742 ◽  
Author(s):  
Philippe F. Weck ◽  
Eunja Kim

The structure, lattice dynamics and thermodynamic properties of bulk technetium were investigated within the framework of density functional theory. The predicted thermal expansion and isobaric heat capacity are in excellent agreement with available experimental data.


2016 ◽  
Vol 18 (15) ◽  
pp. 10320-10328 ◽  
Author(s):  
Z. M. Jendi ◽  
P. Servio ◽  
A. D. Rey

Using density functional theory, the second-order elastic constants, heat capacity, compressibility, and thermal expansion coefficient of methane hydrate were calculated.


2014 ◽  
Vol 16 (1) ◽  
pp. 201-212 ◽  
Author(s):  
Xianhu Zha ◽  
Shuang Li ◽  
Ruiqin Zhang ◽  
Zijing Lin

AbstractDensity functional theory combined with the Grüneisen approximation is used to calculate the thermal properties of single-walled boron nanotubes (BNTs). The specific heat and thermal expansion are investigated. The thermal expansion coefficient of the BNT is found to be significantly correlated with tube size and chirality. A remarkable thermal contraction is found at small tube diameters. These results indicate that BNTs would have potential applications in sensors, actuators, and memory materials.


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