中国物理B ›› 2014, Vol. 23 ›› Issue (8): 86103-086103.doi: 10.1088/1674-1056/23/8/086103

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Two-coupled structural modulations in charge-density-wave state of SrPt2As2 superconductor

王莉a, 王臻a, 施洪龙a b, 陈震a, 蒋复国a, 田焕芳a, 杨槐馨a, 房爱芳a, 王楠林a, 李建奇a   

  1. a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    b School of Science, Minzu University of China, Beijing 100081, China
  • 收稿日期:2014-03-11 修回日期:2014-05-16 出版日期:2014-08-15 发布日期:2014-08-15
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant Nos. 2011CBA00101, 2010CB923002, 2012CB821404, and 2011CB921703), the National Natural Science Foundation of China (Grant Nos. 11190022, 11274368, and 51272277), and the Funds from the Chinese Academy of Sciences.

Two-coupled structural modulations in charge-density-wave state of SrPt2As2 superconductor

Wang Li (王莉)a, Wang Zhen (王臻)a, Shi Hong-Long (施洪龙)a b, Chen Zhen (陈震)a, Chiang Fu-Kuo (蒋复国)a, Tian Huan-Fang (田焕芳)a, Yang Huai-Xin (杨槐馨)a, Fang Ai-Fang (房爱芳)a, Wang Nan-Lin (王楠林)a, Li Jian-Qi (李建奇)a   

  1. a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    b School of Science, Minzu University of China, Beijing 100081, China
  • Received:2014-03-11 Revised:2014-05-16 Online:2014-08-15 Published:2014-08-15
  • Contact: Li Jian-Qi E-mail:ljq@aphy.iphy.ac.cn
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant Nos. 2011CBA00101, 2010CB923002, 2012CB821404, and 2011CB921703), the National Natural Science Foundation of China (Grant Nos. 11190022, 11274368, and 51272277), and the Funds from the Chinese Academy of Sciences.

摘要: Transmission electron microscopy (TEM) study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave (CDW) state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1= 0.62a* on the a*-b* plane and q2= 0.23a* on the a*-c* plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between q1 and q2 can be generally written as q1= (q2+a*)/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr(Pt1-xIrx)2As2 (x ≤ 0.06) could moderately change these CDW modulations and also affect their superconductivities.

关键词: superconductivity, charge-density-wave, structural modulation, transmission electron microscopy

Abstract: Transmission electron microscopy (TEM) study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave (CDW) state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1= 0.62a* on the a*-b* plane and q2= 0.23a* on the a*-c* plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between q1 and q2 can be generally written as q1= (q2+a*)/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr(Pt1-xIrx)2As2 (x ≤ 0.06) could moderately change these CDW modulations and also affect their superconductivities.

Key words: superconductivity, charge-density-wave, structural modulation, transmission electron microscopy

中图分类号:  (Electron diffraction and scattering)

  • 61.05.J-
74.70.Xa (Pnictides and chalcogenides) 71.45.Lr (Charge-density-wave systems) 61.50.Ah (Theory of crystal structure, crystal symmetry; calculations and modeling)