scholarly journals Phenomenological thermodynamics and the structure formation mechanism of the CuTi2S4 rhombohedral phase

2016 ◽  
Vol 18 (15) ◽  
pp. 10600-10606 ◽  
Author(s):  
Michail V. Talanov ◽  
Vladimir B. Shirokov ◽  
Valery M. Talanov
Keyword(s):  
Phase Transition ◽  
Structure Formation ◽  
Formation Mechanism ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Rhombohedral Phase

The theory of structural phase transition in CuTi2S4 is proposed.

First-Principles Study of Lattice Dynamics, Structural Phase Transition, and Thermodynamic Properties of Barium Titanate

2016 ◽  
Vol 71 (8) ◽  
pp. 759-768 ◽  
Author(s):  
Huai-Yong Zhang ◽  
Zhao-Yi Zeng ◽  
Ying-Qin Zhao ◽  
Qing Lu ◽  
Yan Cheng
Keyword(s):  
Phase Transition ◽  
Barium Titanate ◽  
Thermodynamic Properties ◽  
Structural Phase Transition ◽  
First Principles ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Structural Phase ◽  
Rhombohedral Phase ◽  
Site Symmetry

AbstractLattice dynamics, structural phase transition, and the thermodynamic properties of barium titanate (BaTiO3) are investigated by using first-principles calculations within the density functional theory (DFT). It is found that the GGA-WC exchange-correlation functional can produce better results. The imaginary frequencies that indicate structural instability are observed for the cubic, tetragonal, and orthorhombic phases of BaTiO3 and no imaginary frequencies emerge in the rhombohedral phase. By examining the partial phonon density of states (PDOSs), we find that the main contribution to the imaginary frequencies is the distortions of the perovskite cage (Ti-O). On the basis of the site-symmetry consideration and group theory, we give the comparative phonon symmetry analysis in four phases, which is useful to analyze the role of different atomic displacements in the vibrational modes of different symmetry. The calculated optical phonon frequencies at Γ point for the four phases are in good agreement with other theoretical and experimental data. The pressure-induced phase transition of BaTiO3 among four phases and the thermodynamic properties of BaTiO3 in rhombohedral phase have been investigated within the quasi-harmonic approximation (QHA). The sequence of the pressure-induced phase transition is rhombohedral→orthorhombic→tetragonal→cubic, and the corresponding transition pressure is 5.17, 5.92, 6.65 GPa, respectively. At zero pressure, the thermal expansion coefficient αV, heat capacity CV, Grüneisen parameter γ, and bulk modulus B of the rhombohedral phase BaTiO3 are estimated from 0 K to 200 K.

Structural Phase Transition of Multilayer VSe2

2020 ◽  
Vol 12 (22) ◽  
pp. 25143-25149 ◽  
Author(s):  
Dian Li ◽  
Xiong Wang ◽  
Chi-ming Kan ◽  
Daliang He ◽  
Zejun Li ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase

scholarly journals Raman spectroscopy study of the behavior of the soft mode in a structural phase transition in the Pr3Sb5O12 crystal

2015 ◽  
Vol 57 (11) ◽  
pp. 2286-2289 ◽  
Author(s):  
A. S. Oreshonkov ◽  
A. K. Khodzhibaev ◽  
A. S. Krylov ◽  
M. F. Umarov ◽  
A. N. Vtyurin
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Structural Phase Transition ◽  
Soft Mode ◽  
Structural Phase ◽  
Spectroscopy Study

High-pressure structural phase transition and metallization in Ga2S3 under non-hydrostatic and hydrostatic conditions up to 36.4 GPa

2021 ◽  
Author(s):  
Linfei Yang ◽  
Jianjun Jiang ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Meiling Hong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Structural Properties ◽  
Structural Phase Transition ◽  
First Principles ◽  
Theoretical Calculations ◽  
Structural Phase

The vibrational, electrical and structural properties of Ga2S3 were explored by Raman spectroscopy, EC measurements, HRTEM and First-principles theoretical calculations under different pressure environments up to 36.4 GPa.

scholarly journals Study of the structural phase transition in diamond (100) & (111) surfaces

Carbon Trends ◽  
2021 ◽  
Vol 3 ◽  
pp. 100033
Author(s):  
H. Gomez ◽  
M.N. Groves ◽  
M.R. Neupane
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase

The structural phase transition of ammonia borane under high pressure

2020 ◽  
Vol 45 (58) ◽  
pp. 33047-33058
Author(s):  
Lan-Ting Shi ◽  
Cui-E Hu ◽  
Alfonso Muñoz ◽  
Lin-Xiang Ji ◽  
Yao-Yao Huang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Ammonia Borane
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