Dresden 2017 – wissenschaftliches Programm
MM 62.5: Vortrag
Donnerstag, 23. März 2017, 12:45–13:00, IFW B
Pressure-induced ferroelastic phase transition in SnO2 from density functional theory — •Lei Yang, Weiliu Fan, Yanlu Li, Lei Wei, and Xian Zhao — Shandong University
We studied the high-pressure ferroelastic transition of rutile- to CaCl2-type SnO2 within density functional theory and Landau free energy theory. Softening mechanism of B1g mode (order parameter Q) and the coupling mechanism between the soft B1g mode and the soft transverse acoustic (TA) mode (strain ε) are clarified by calculating Landau energy map around the ground state. It is found that the Sn-O-Sn bending induced soft B1g mode effectively reduces the excess energy increase caused by bond stretching, which however always leads to SnO6 octahedral distortion. The octahedral distortion is subsequently minimized by lattice distortion strain ε, which interacts with the soft B1g mode to further increase the stability of system.