,Superconductivity Tuned by the Iron Vacancy Order in KxFe2_ySe2

• 作 者: BAO Wei LI Guan-Nan HUANG Qing-Zhen CHEN Gen-Fu HE Jun-Bao WANG Du-Ming M.A. Green
• 机 构: Department of Physics, Renmin University of China, Beijing 100872“,”NIST Center for Neutron Research
• 出 处: 中国物理快报（英文版）
• 发表日期: 2013年2期

The recently discovered alkali metal (A=K,Rb,Cs,Tl-K or Tl Rb) intercalated iron selenide superconductors[1-4] achieve a transition temperature (Tc ～ 30K) much higher than in previous iron selenide (11) superconductors (Tc ≤ 14 K)[5] at ambient pressure.They are initially thought to be isostructural to BaFe2As2,and the Fe valence at 1.6+ implied by chemical formulas A0.sFe2Se2 seems to be supported by ARPES studies.[6] However,vacancies have been intentionally introduced in the Fe plane in the Tl-containing superconductors,[3] and various Fe vacancy orders have also been directly observed in the K intercalated materials in transmission electron microscopy (TEM) studies.