title: Superconductivity Induced by Oxygen Doping in Y2O2Bi.
abstract: When doped with oxygen, the layered Y2O2Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first-principles calculations for undoped and O-doped Y2O2Bi. The preferred sites for doped O atoms are the centers of Bi4squares in the Bi square net. Several Bi 6p x/y bands of Y2O2Bi are raised in energy by oxygen doping because the 2p x/y orbitals of the doped oxygen make antibonding possible with the 6p x/y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the "flat/steep" band model for superconductivity is satisfied in O-doped Y2O2Bi.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou, 350002, China.
authors.forename: Xiyue
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA.
authors.forename: Elijah E
authors.initials: EE
authors.lastname: Gordon
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou, 350002, China.|Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA.
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Whangbo
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS), Fuzhou, 350002, China.
authors.forename: Shuiquan
authors.initials: S
authors.lastname: Deng
keywords: band structure; first-principles calculations; flat band; superconductivity; yttrium bismuth oxide