Superconductivity in BaTi2Sb2O with a d1 square lattice

Abstract

We prepared a new two-dimensional oxyantimonide, BaTi(2)Sb(2)O, which shows a superconducting transition at 1.2 K, representing the first superconductivity in a system with Ti(3+) (d(1)) in a square lattice. The TiO(2)Sb(4) mixed anionic coordination stabilizes a unique half-filled Ti d(xy) orbital configuration in Ti(2)O plane, which is analogous to Cu(2+) (d(9)) in the high-T(c) 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 BaTi(2)As(2)O. © 2012, Physical Society of Japan