scholarly journals Evolution of the Structural, Mechanical, and Phonon Properties of GeSe Polymorphs in a Pressure-Induced Second-Order Phase Transition

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3612 ◽  
Author(s):  
Jianhui Yang ◽  
Qiang Fan ◽  
Bing Xiao ◽  
Yingchun Ding

A pressure-induced structural transition from the layered-like phase (Pnma) to another bilayer structure (Cmcm) in GeSe was investigated with first principle calculations. The variations of the structural, electronic, elastic, and vibrational properties of GeSe with the application of pressure were obtained. The transformation from the Pnma to Cmcm phase occurred at 34 GPa. The Cmcm phase structure showed dynamical stability above 37 GPa. The lattice parameters and the equation of state varied continuously at the transition pressure. Obvious stiffening in the C33 and C23 elastic constants associated with the compressive and shear components was observed to occur within the phase transition process. Two characteristic Raman modes (Ag and B3g) of the Pnma phase showed significant softening by increasing the pressure.

2018 ◽  
Vol 427 ◽  
pp. 304-311 ◽  
Author(s):  
Yifan Meng ◽  
Kang Huang ◽  
Zhou Tang ◽  
Xiaofeng Xu ◽  
Zhiyong Tan ◽  
...  

Langmuir ◽  
2016 ◽  
Vol 32 (26) ◽  
pp. 6691-6700 ◽  
Author(s):  
Zhangxin Ye ◽  
Youcheng Li ◽  
Zesheng An ◽  
Peiyi Wu

Author(s):  
Longjian Li ◽  
Jianbang Zeng ◽  
Quan Liao ◽  
Wenzhi Cui

A new lattice Boltzmann model, which is based on Shan-Chen (SC) model, is proposed to describe liquid-vapor phase transitions. The new model is validated through simulation of the one-component phase transition process. Compared with the simulation results of van der Waals fluid and the Maxwell equal-area construction, the results of new model are closer to the analytical solutions than those of SC model and Zhang model. Since the range of temperature and the maximum density ratio are increased, and the value of maximum spurious current is between those of SC and Zhang models, it is believed that this new model has better stability than SC and Zhang models. Therefore, the application scope of this new model is expanded. According to the principle of corresponding states in Engineering Thermodynamics, the simulations of water and ammonia phase transition process are implemented by using this new model with different equations of state. Compared to the experimental data of water and ammonia, the results show that the Peng-Robinson equation of state is more suitable to describe the water, ammonia and other substances phase transition process. Therefore, these simulation results have great significance for the real engineering applications.


2002 ◽  
Vol 16 (27) ◽  
pp. 1021-1026 ◽  
Author(s):  
ARANYABHUTI BHATTACHERJEE ◽  
MAN MOHAN

Crossover from individual Rabi dynamics to collective Josephson dynamics in two-coupled Bose–Einstein condensates is studied as a phase transition process. We obtain the critical value of the parameter Λ (ratio of the mean field energy to the tunneling matrix element) for the π-phase oscillations from the non-linear perturbation expansion of small oscillations around the saddle point of the first-order Euclidean (imaginary time) differential equations for polar and azimuthal angles θ and ϕ without approximation.


2019 ◽  
Vol 125 (20) ◽  
pp. 204303
Author(s):  
Abhinav Kumar ◽  
Alejandro Strachan ◽  
Nicolas Onofrio

2009 ◽  
Vol 54 (24) ◽  
pp. 4596-4603 ◽  
Author(s):  
JianBang Zeng ◽  
LongJian Li ◽  
Quan Liao ◽  
WenZhi Cui ◽  
QingHua Chen ◽  
...  

RSC Advances ◽  
2015 ◽  
Vol 5 (101) ◽  
pp. 83139-83143 ◽  
Author(s):  
Huafang Zhang ◽  
Quanjun Li ◽  
Pengfei Shen ◽  
Qing Dong ◽  
Bo Liu ◽  
...  

Micro-sized rods show a lower phase transition temperature than nano-sized rods, and this is interpreted on the basis of nucleating defects.


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