Thermodynamic properties of glassy phonon states induced by strong electron correlations in 𝜃-type organic charge transfer salts

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040059 ◽  
Author(s):  
T. Nomoto ◽  
E. Yesil ◽  
S. Yamashita ◽  
H. Akutsu ◽  
Y. Nakazawa
Keyword(s):  
Heat Capacity ◽  
Charge Transfer ◽  
Thermodynamic Properties ◽  
Glassy State ◽  
Debye Model ◽  
Low Energy ◽  
Electron Correlations ◽  
Strong Electron ◽  
Charge Transfer Salts ◽  
Spin Moments

The appearance of electron correlations–induced glassy state of low-energy phonons in the non-dimeric organic charge transfer salt in [Formula: see text]-(BEDT-TTF)2CsZn(SCN)4 is considered as a strong evidence of charge lattice coupling in molecular charge transfer salts. We discuss the temperature and the magnetic field dependences of the heat capacity of this salt in terms of the soft potential model to describe the thermodynamic properties of enhanced phonons that occur in molecular glasses. The evaluated [Formula: see text] term of [Formula: see text]-(BEDT-TTF)2CsZn(SCN)4 is about 30 mJ K[Formula: see text] mol[Formula: see text], which is much larger than other charge transfer salts described by the low-temperature approximation of the Debye model. The magnetic fields dependence of the boson peak is almost negligible, but the low-energy term, for example, in the temperature-linear term of heat capacity shows a slight change, probably due to the small amount of localized spin moments. The comparison with other systems is also performed.

Study of Thermodynamic Properties of Superhard w-BC2N

2013 ◽  
Vol 750-752 ◽  
pp. 1141-1145
Author(s):  
Ai Ling Ding ◽  
Feng Li ◽  
Chun Mei Li ◽  
Jing Ao ◽  
Zhi Qian Chen
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Method ◽  
Debye Model ◽  
Theory Method ◽  
Density Approximation ◽  
Functional Theory

We investigate the thermodynamic properties of superhard w-BC2N by using ab initio plane-wave pseudopotential density functional theory method within local density approximation (LDA). Through the quasi-harmonic Debye model, we investigate the thermodynamic properties of w-BC2N. The variation of the thermal expansion, the heat capacity and the Gruneisen parameter γ with pressure P and temperature T, and many other thermodynamic parameters of w-BC2N are obtained systematically.

First-Principles Calculations of Elastic and Thermodynamic Properties of Cubic CdTe

2011 ◽  
Vol 268-270 ◽  
pp. 886-891
Author(s):  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Lattice Constants ◽  
Temperature And Pressure ◽  
The Relationship

the equilibrium lattice constants, elastic and thermodynamic properties of cubic CdTe are systemically investigated at high temperature using the plane-wave pseudopotential method as well as the quasi-harmonic Debye model. The bulk modulus of CdTe are calculated as a function of temperature up to 1000K, the relationship between bulk modulusBand pressure is also obtained. The results gained from this model will provide overall predictions accurately for the temperature and pressure dependence of various quantities such as the bulk modulus, the heat capacity and the thermal expansion coefficient. More over, the dependences between Debye temperature and temperature are also successfully obtained. Our results are compared with the experimental data and discussed in light of previous works.

THERMODYNAMIC PROPERTIES OF MC (M = V, Nb, Ta): FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (19) ◽  
pp. 1341035 ◽  
Author(s):  
YONG CAO ◽  
JINGCHUAN ZHU ◽  
YONG LIU ◽  
ZHISHEN LONG
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Linear Expansion ◽  
Debye Model ◽  
Linear Expansion Coefficient ◽  
First Principles Calculations ◽  
Temperature Dependences

Through the quasi-harmonic Debye model, the pressure and temperature dependences of linear expansion coefficient, bulk modulus, Debye temperature and heat capacity have been investigated. The calculated thermodynamic properties were compared with experimental data and satisfactory agreement is reached.

Estimation of the heat capacity of CdTe semiconductor

2016 ◽  
Vol 30 (04) ◽  
pp. 1650026 ◽  
Author(s):  
Hüseyin Koç ◽  
Erhan Eser
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Binomial Coefficient ◽  
Debye Model ◽  
The Other ◽  
Temperature Range ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide a simple and reliable analytical expression for the thermodynamic properties calculated in terms of the Debye model using the binomial coefficient, and examine specific heat capacity of CdTe in the 300–1400 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. The calculated results are in good agreement with the other results over the entire temperature range.

First-Principles Investigations on Structural, Elastic, and Thermodynamic Properties of Ce-La Alloys Under High Pressure

2014 ◽  
Vol 69 (1-2) ◽  
pp. 52-60
Author(s):  
Li-Qin Zhang ◽  
Yan Cheng ◽  
Zhen-Wei Niu ◽  
Guang-Fu Ji
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Electronic Properties ◽  
Ground State ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Charge Densities

The structural stability, thermodynamic, elastic, and electronic properties of cerium (Ce)- lanthanum (La) alloys were investigated for different Ce/La ratios under pressure by first-principles calculations using on-the-fly (OTF) pseudopotential and general gradient approximation (GGA). The ground-state properties of lanthanum and cerium obtained by minimizing the total energy agree favourably with other work.We derived the elastic constants, bulk modulus, and shear modulus of the La-Ce alloys for different Ce/La ratios. Using the quasi-harmonic Debye model, the thermodynamic properties of the La-Ce alloys including the thermal expansion coefficient α and heat capacity Cv are successfully obtained in the temperature range from 0 K to 1000 K. Furthermore, the electronic properties such as density of states and charge densities were also studied.

Theoretical Investigations on Elastic and Thermodynamic Properties of CdTe

2012 ◽  
Vol 534 ◽  
pp. 192-196
Author(s):  
Yu Hong Huang ◽  
Wan Qi Jie ◽  
Gang Qiang Zha
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Debye Model ◽  
Extreme Conditions ◽  
Functional Theory ◽  
Opposite Case ◽  
Theoretical Investigations

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.

The mechanical and thermodynamic properties of ZrAl2 under pressure from first-principles investigation

2016 ◽  
Vol 27 (01) ◽  
pp. 1650001
Author(s):  
Ning Wei ◽  
Xuefei Wang ◽  
Xuzhong Zuo
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Thermodynamic Properties ◽  
Debye Temperature ◽  
First Principles ◽  
Density Functional ◽  
Applied Pressure ◽  
Debye Model ◽  
Effect Of Temperature ◽  
Expansion Formula

The mechanical and thermodynamic properties of ZrAl2 alloy under high pressure are investigated by first-principles based on the density functional theory. Due to all the elastic constants of ZrAl2 alloy satisfy generalized stabilities criteria, ZrAl2 is mechanically stable under pressure up to 100[Formula: see text]GPa. By analyzing the value of B/G and Poisson’s ratio [Formula: see text] which are correlated with the ductility and brittleness of material, we found that ZrAl2 belongs to brittle material at pressure of 0–70[Formula: see text]GPa and will change from brittleness to ductility at 70[Formula: see text]GPa. Combining with high bulk modulus B and shear modulus G, the mechanical of properties will be improved under high pressure. Moreover, the thermodynamic properties, such as the Debye temperature [Formula: see text], heat capacity [Formula: see text] and thermal expansion [Formula: see text], are discussed using the quasi-harmonic Debye model. We noted that the Debye temperature [Formula: see text] is mainly dependent on the pressure and the effect of temperature on the heat capacity [Formula: see text] is more important than the applied pressure.

High-pressure phase transition and thermodynamic properties of MgSe: Ab initio study

2009 ◽  
Vol 87 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Hongzhi Fu ◽  
WenFang Liu ◽  
Tao Gao
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Cesium Chloride ◽  
Debye Model ◽  
Relative Volume ◽  
Rock Salt Structure ◽  
High Pressure Phase Transition ◽  
Salt Structure ◽  
Pressure Phase

The transition phase of MgSe from a rock salt structure (B1) to a cesium chloride structure(B2) is investigated by ab initio calculations. The thermodynamic properties of the B1 and B2 structures are obtained through the quasi-harmonic Debye model. Moreover, the dependences of the relative volume V/V0 on the pressure P, the Debye temperature Θ, and heat capacity CV on the pressure P, as well as the heat capacity CV on the temperature T are estimated.

Structure and Physical Properties of EDT-TTF Salts

1997 ◽  
Vol 488 ◽  
Author(s):  
Tetsuo Kondo ◽  
Lyudmila A. Kushch ◽  
Hideki Yamochi ◽  
Gunzi Saito
Keyword(s):  
Activation Energy ◽  
Charge Transfer ◽  
Band Structure ◽  
Electron Correlation ◽  
Room Temperature ◽  
Structural Deformation ◽  
Strong Electron Correlation ◽  
Strong Electron ◽  
One Dimensional ◽  
Charge Transfer Salts

AbstractCharge-transfer salts of EDT-TTF with tetrahedral anions MX4 (M=Fe, Ga ; X=Cl, Br) were prepared. They are isostructural to each other (monoclinic P21/m) with the stoichiometry of 2:1. All of them are semiconductors having the conductivity at room temperature of 5 to 9 Scm−1 and activation energy of 40 to 170 meV. Since the calculated band structure of them indicate that they should be quasi one-dimensional metals, they were discussed from the point of structural deformation and strong electron correlation.

Evidence for Strong Electron-Electron Correlations in (MTPP)1-x (MTPA)X (TCNQ)2

1982 ◽  
Vol 85 (1) ◽  
pp. 225-231
Author(s):  
G. Croteau ◽  
Amir Lakhani ◽  
N. K. Hota
Keyword(s):  
Electron Correlations ◽  
Strong Electron
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