Department of Chemistry, University of Houston, Houston, Texas 77204, USA.
J Am Chem Soc. 2012 Oct 10;134(40):16520-3. doi: 10.1021/ja3078889. Epub 2012 Sep 28.
A new layered Ti-based pnictide oxide superconductor, Ba(1-x)Na(x)Ti(2)Sb(2)O (0.0 ≤ x ≤ 0.33), is reported. X-ray studies revealed that it crystallizes in the tetragonal CeCr(2)Si(2)C structure. The undoped parent compound, BaTi(2)Sb(2)O [P4/mmm; a = 4.1196(1) Å; c = 8.0951(2) Å], exhibits a charge density wave (CDW)/spin density wave (SDW) transition at 54 K. Upon chemical doping with Na, the CDW/SDW transition is systematically suppressed, and superconductivity arises with the critical temperature (T(c)) increasing to 5.5 K. Bulk superconductivity was confirmed by resistivity, magnetic, and heat capacity measurements. Like the high-T(c) cuprates and the iron pnictides, the superconductivity in BaTi(2)Sb(2)O arises from an ordered state. Similarities and differences between BaTi(2)Sb(2)O and the cuprate and iron pnictide superconductors are discussed.
一种新的层状钛基磷化物氧化物超导体 Ba(1-x)Na(x)Ti(2)Sb(2)O（0.0 ≤ x ≤ 0.33）被报道。X 射线研究表明，它结晶为四方的 CeCr(2)Si(2)C 结构。未掺杂的母体化合物 BaTi(2)Sb(2)O[P4/mmm; a = 4.1196(1)Å; c = 8.0951(2)Å]在 54 K 时表现出电荷密度波（CDW）/自旋密度波（SDW）转变。通过化学掺杂 Na，CDW/SDW 转变被系统地抑制，超导性出现，临界温度（T(c)）增加到 5.5 K。通过电阻率、磁性和比热测量证实了体超导性。与高温铜酸盐和铁磷化物类似，BaTi(2)Sb(2)O 中的超导性来自有序态。讨论了 BaTi(2)Sb(2)O 与铜酸盐和铁磷化物超导体之间的相似点和不同点。
