The PZT material near the morphotropic phase boundary where a monoclinic phase was observed is studied in this paper. A theory of the tetragonal to monoclinic phase transition was developed within the Landau free energy approach. The order parameter is the electric polarization vector. The phase transition from the tetragonal to the monoclinic phase is of the first order near the second order. ...

S. Moser,1,* N. E. Shaik,1 D. Samal,2,3 S. Fatale,1 B. Dalla Piazza,1 M. Dantz,4 J. Pelliciari,4 P. Olalde-Velasco,4 T. Schmitt,4 G. Koster,2 F. Mila,5 H. M. Rønnow,1 and M. Grioni1 1Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland 2MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede,...

X-ray diffraction (XRD) rocking-curves were measured for tetragonal hen egg white (HEW) lysozyme crystals grown with and without application of an external electric field, and the crystal quality was assessed according to the full width at half-maximums (FWHMs) of each rocking-curve profile. The average FWHMs for tetragonal HEW lysozyme crystals grown with an external electric field at 1 MHz we...

The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the hightemperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type ant...

The small exciton binding energy of perovskite suggests that the long-lived photoluminescence and slow recovery of the ground state bleaching of the tetragonal phase at room temperature results primarily from the decay of free charges rather than the decay of the initially created excitons. Here we demonstrate the ground state bleaching recovery of the orthorhombic phase of methylammonium lead ...

It is shown that LaTiO3, in superlattices with SrTiO3, is a strongly correlated metal rather than a Mott insulator. The tetragonal lattice geometry imposed by the SrTiO3 substrate leads to an increase of the Ti 3dt2g bandwidth and a reversal of the t2g crystal field relative to the orthorhombic bulk geometry. Using dynamical mean field theory based on finite-temperature multiband exact diagonal...