Neutron powder diffraction and inelastic neutron scattering experiments were performed to clarify the mechanism of phase transition and protonic conductivity of K3H(SeO4)2. A rotational SeO4 tetrahedra mode at the zone boundary L -point accounts for the symmetrical change in space group from R 3̄ m to C2/c. No significantly anomaly was observed in the transversal acoustic and under-damped optical modes, while a broad spectrum was observed around 0 meV at the L -point above T C. The spectrum depends on the temperature and the dependence is represented by the soft mode due to an over-damped phonon both Q and energy space. The rotational mode of tetrahedra drives the improper ferroelastic phase transition.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2009 Oct 7|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics