Top-Seeded Solution Growth, Structure, Morphology, and Functional Properties of a New Polar Crystal - Cs2TeW3O12

Single crystals of the polar material Cs2TeW3O12 (CTW) with dimensions up to 26 x 18 x 4 mm(3) were successfully grown using a top-seeded solution growth method. The morphologies of the as-grown crystals have been described and compared with that obtained from the Bravais-Friedel and Donnay-Harker (BFDH) method. The crystal structure of CTW has been solved for the first time using single-crystal X-ray diffraction: the compound crystallizes in polar hexagonal space group P6(3) (No. 173) with cell parameters a = b = 7.3279(3) angstrom, c = 12.4075(5) angstrom, Z = 2, and V = 577.00(4) angstrom(3). Thermal analysis shows that CTW is thermally stable up to 820 degrees C, at which it melts incongruently. Further high-resolution X-ray diffraction experiments gave a full-width at half-maximum of the rocking curve of 33 '', indicating a good crystalline quality for the as-grown crystals. Optical transmittance spectra of CTW show a broad transmission range from 410 to 5310 nm. Powder second-harmonic generation (SHG) measurements with a 1064 nm laser indicates that CTW exhibits a strong SHG efficiency of about 1.5 the one of KTiOPO4. Polarization measurements indicate that CTW is not ferroelectric; i.e., the polarization is not switchable. In addition, CTW is nonhygroscopic and resistant to diluted HNO3 aqua-solution.