scholarly journals High pressure phase transition and phonon-dispersion relations of BeO calculated by first-principles method

2010 ◽  
Vol 59 (12) ◽  
pp. 8755
Author(s):  
Yuan Peng-Fei ◽  
Zhu Wen-Jun ◽  
Xu Ji-An ◽  
Liu Shao-Jun ◽  
Jing Fu-Qian
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
First Principles ◽  
Phonon Dispersion ◽  
Dispersion Relations ◽  
High Pressure Phase ◽  
High Pressure Phase Transition ◽  
Pressure Phase ◽  
Phonon Dispersion Relations ◽  
First Principles Method

First-principles studies of phase transition and structural stability of SrC2 under pressure

2014 ◽  
Vol 28 (24) ◽  
pp. 1450190 ◽  
Author(s):  
Yi-Lin Lu ◽  
Hui Zhao
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
First Principles ◽  
Phonon Dispersion ◽  
Covalent Bond ◽  
Text Structure ◽  
High Pressure Phase ◽  
Space Group ◽  
Type Space ◽  
Pressure Phase

Pressure-induced phase transitions in SrC 2 are investigated using the first-principles plane wave pseudopotential method within the generalized gradient approximation. The phase transition from monoclinic phase ( CaC 2-II-type, space group C2/c) to trigonal ( CaC 2-VII-type, space group [Formula: see text]) structure is predicted to occur at 10.4 GPa. The high-pressure phase is thermodynamic, mechanically and dynamically stable, as verified by the calculations of its formation energy, elastic stiffness constants and phonon dispersion. Further the electronic analysis predicates this high-pressure phase to be an insulator. When increasing pressure, the ionic bond between C and Sr is strengthened, as well is the covalent bond between C and C , however, the increase of the ionic interaction between Sr and C preponderates over that of the covalent bond interaction, so the gap is narrowed.

Sign in / Sign up

Export Citation Format

Share Document