标题：Pressure-induced ferroelastic phase transition in SnO2from density functional theory
作者：Yang, Lei ;Fan, Weiliu ;Li, Yanlu ;Wei, Lei ;Zhao, Xian
作者机构：[Yang, Lei ;Wei, Lei ;Zhao, Xian ] State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;[Li, Yanlu ] Lehrstuhl für 更多
来源：Journal of Chemical Physics
摘要：High-pressure ferroelastic transition of rutile- to CaCl2-type SnO2is investigated within density functional theory and Landau free energy theory. The calculated Landau energy map around the ground state is successfully used to clarify the softening mechanism of B1gmode (order parameter Q) and the coupling mechanism between the soft B1gmode and the soft transverse acoustic (TA) mode (strain Ε). It is found that the Sn-O-Sn bending induced soft B1gmode effectively slows the excess energy increase caused by bond stretching, while the coupling between the soft B1gmode and the soft TA mode further decreases the energy since the lattice distortion strain Ε minimizes the SnO6octahedral distortion. Q induced Landau Gibbs free energy is interpreted as the sum of the bond stretching energy, bending energy, and octahedral distortion energy, while that induced by Ε is interpreted as the lattice distortion energy. © 2014 AIP Publishing LLC.