title: LiNbO3-Type Oxide (Tl(1-x)Sc(x))ScO3: High-Pressure Synthesis, Crystal Structure, and Electronic Properties.
abstract: We investigate the synthesis of a thallium scandate, TlScO3, under high-pressure (6-7.7 GPa) and high-temperature (1373-1773 K) conditions. At 6 GPa, a LiNbO3-type phase appears in a narrow temperature range and in mixtures with other phases. At 7.7 GPa and 1673 K, a new LiNbO3-type oxide is found with a composition of (Tl(1-x)Sc(x))ScO3 and x ≈ 0.26 as determined by structural analysis from X-ray powder diffraction data. It crystallizes in space group R3c (No. 161) with lattice parameters of a = 5.50283(7) Å and c = 14.4606(2) Å. It is stable at least up to 800 K at ambient pressure. The point-charge model gives an electric polarization of 60 μC/cm(2). First-principles calculations show that centrosymmetric ilmenite-type and polar LiNbO3-type structures of stoichiometric TlScO3 have almost the same lowest energy, and the next stable structure is a GdFeO3-type perovskite structure.
authors: International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS) , Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.
authors: Alexei A
authors: AA
authors: Belik
authors: International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS) , Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.|Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences , Beijing 100190, China.
authors: Wei
authors: W
authors: Yi
authors: Yu
authors: Y
authors: Kumagai
authors: Synchrotron X-ray Station at SPring-8, NIMS , Kouto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan.
authors: Yoshio
authors: Y
authors: Katsuya
authors: Synchrotron X-ray Station at SPring-8, NIMS , Kouto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan.
authors: Masahiko
authors: M
authors: Tanaka
authors: Fumiyasu
authors: F
authors: Oba