Synthesis and High-Pressure Study of Corundum-Type In2O3
This work reports the high-pressure and high-temperature (HP-HT) synthesis of pure rhombohedral (corundum-type) phase of indium oxide (In2O3) from its most stable polymorph, cubic bixbyite-type In2O3, using a multianvil press. Structural and vibrational properties of corundum-type In2O3 (rh-In2O3) have been characterized by means of angle-dispersive powder X-ray diffraction and Raman scattering measurements at high pressures which have been compared to structural and lattice dynamics ab initio calculations. The equation of state and the pressure dependence of the Raman-active modes of the corundum-type phase are reported and compared to those of corundum (α-Al2O3). It can be concluded that …
Raman spectra of (PbS)1.18(TiS2)2 misfit compound
Abstract A Raman study on the (PbS)1.18(TiS2)2 semiconductor structure with incommensurate layers (misfit) is reported. The different bands observed in the spectra are attributed to both the TiS2 host layers, at 219 (Eg) and 333 (A1g) cm−1, and the intercalated PbS layers: the LO(Γ), 2LO and 3LO phonons at 203, 412 and 634 cm−1, respectively. A phonon peak probably related to the superposition of TiS2 and PbS vibrations, was observed near 286 cm−1. The decrease of the phonon wave numbers (of the modes located at 203, 333, 412, and 634 cm−1) with increasing laser power pointed out negative temperature coefficients of these modes. A peak appearing with laser power near 151 cm−1 is discussed. …