2007/02/16 by Johannes Frantti, J. Frantti, Y. Fujioka +4
Engineering · Physics and Astronomy · #Advanced MEMS and NEMS Technologies #FOS: Physical sciences #Geophysics and Sensor Technology #Materials Science (cond-mat.mtrl-sci) #Mechanical and Optical Resonators #Other Condensed Matter (cond-mat.other) #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.48550/arxiv.cond-mat/0702388
arxiv created 2007/02/16 · openalex publication_date 2007/02/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Our first-principles computations show that the ground state of PbTiO3 under hydrostatic pressure transforms discontinuously from P4mm to R3c at 9 GPa. Spontaneous polarization decreases with increasing pressure so that the R3c phase transforms to the centrosymmetric R3c phase at around 30 GPa. The first-order phase transition between tetragonal and rhombohedral phase is exceptional since there is no evidence for a bridging phase. The essential feature of the R3c and R3c phases is that they allow the oxygen octahedron to increase its volume VB at the expense of cuboctahedral volume VA around a Pb ion. This is further supported by the fact that neither the R3m nor Cm phase, which keep the VA/VB ratio constant, is a ground state within the pressure range between 0 and 40 GPa. Thus tetragonal strain is dominant up to 9 GPa, whereas at higher pressures efficient compression through oxygen octahedra tilting plays the central role for PbTiO3. Previously predicted pressure induced colossal enhancement of piezoelectricity in PbTiO3 corresponds to unstable Cm and R3m phases. This suggests that the phase instability, in contrast to the polarization rotation, is responsible for the large piezoelectric properties observed in systems like Pb(Zr,Ti)O3 in the vicinity of the morphotropic phase boundary.