title: Preparation and characterization of a possible topological insulator BiYO3: experiment versus theory.
abstract: The Bi-Y-O system has been investigated by X-ray powder diffraction, electron diffraction, UV-vis and IR experiments. A metastable cubic high temperature phase of BiYO3 with fluorite-type structure has been structurally characterized for the first time and shows a large band gap of ∼ 5.9 eV. A unified description for the numerous structural variants discovered in the Bi-Y-O system is established within the symmetry breaking approach. This rich structural phenomenon makes the Bi-Y-O system a promising candidate in the search for new topological insulators for applications. On this basis, a long standing controversy on the phase diagram of the Bi-Y-O system has been solved. Our DFT calculations predict a high pressure phase for BiYO3 with perovskite (ABO3) structure and ordering of Bi and Y on the A and B sites, respectively. However, our analysis of the nature of the low energy electronic structure shows that this phase is not a suitable candidate for a topological insulator.
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China and Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou, Fujian 350002, China. sdeng@fjirsm.ac.cn.
authors.forename: S
authors.initials: S
authors.lastname: Deng
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China.
authors.forename: M
authors.initials: M
authors.lastname: Pan
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China.
authors.forename: M
authors.initials: M
authors.lastname: Lei
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China.
authors.forename: X
authors.initials: X
authors.lastname: Kan
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center (SRDC), Southwest Jiaotong University, Mail stop 165#, Chengdu, 610031, China and School of Materials Science and Engineering University of New South Wales, Sydney, 2052 NSW, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Max-Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany. j.koehler@fkf.mpg.de.
authors.forename: J
authors.initials: J
authors.lastname: Köhler