Superconductivity in BaTi2Sb2O with a d1 Square Lattice

Year: 2012 DOI: 10.1143/JPSJ.81.103706

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Takeshi Yajima, Kousuke Nakano, Fumitaka Takeiri, Toshio Ono, Yuko Hosokoshi, Yoshitaka Matsushita, James Hester, Yoji Kobayashi, Hiroshi Kageyama.   Journal of the Physical Society of Japan, 2012, 81, 103706/1-4.


We prepared a new two-dimensional oxyantimonide, BaTi2Sb2O, which shows a superconducting transition at 1.2 K, representing the first superconductivity in a system with Ti3+ (d1) in a square lattice. The TiO2Sb4 mixed anionic coordination stabilizes a unique half-filled Ti dxy orbital configuration in Ti2O plane, which is analogous to Cu2+ (d9) in the high-Tc superconductors. A charge density wave (CDW)- or spin density wave (SDW)-like anomaly appears at 50 K, which is significantly reduced compared with 200 K for the isostructural and non-superconducting BaTi2As2O.