Low temperature Pmmm and C2/m phases in Sr_2CuO_(3+δ) high temperature superconductor  

作　　者：Hai-Bo Wang Zhen-Lin Luo Yuan-Jun Yang Qing-Qing Liu Si-Xia Hu Meng-Meng Yang Chang-Qing Jin Chen Gao 王海波;罗震林;杨远俊;刘清青;胡思侠;杨蒙蒙;靳常青;高琛(Tonghua Normal University;National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology,University of Science and Technology of China;Institute of Physics, Chinese Academy of Sciences;CAS Key Laboratory of Materials for Energy Conversion and Collaborative Innovation Center of Chemistry for Energy Materials,University of Science and Technology of China)

机构地区：[1]Tonghua Normal University [2]National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology,University of Science and Technology of China [3]Institute of Physics, Chinese Academy of Sciences [4]CAS Key Laboratory of Materials for Energy Conversion and Collaborative Innovation Center of Chemistry for Energy Materials,University of Science and Technology of China

出　　处：《Chinese Physics B》2019年第5期206-209,共4页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program of China(Grant Nos.2012CB922004/3,2010CB934501,and 2009CB929502);the Funds of Jilin Province,China(Grant No.JJKH20180860KJ);the National Natural Science Foundation of China;the Fundamental Research Funds for the Central Universities,China(Grant No.WK2310000043)

摘　　要：A new low temperature Pmmm(120 K) phase was found in high temperature superconductor Sr_2 CuO_(3+δ), which was indicated as a pure electronic phase by resonant x-ray diffraction at Cu K-edge. As shown by x-ray absorption fine structure(EXAFS) and x-ray absorption near edge structure(XANES) at Cu K-edge, the strong charge density redistribution and local lattice fluctuations around Cu site at the onset of phase transition were due to the occurrence of superconductive coherence, the redistribution and fluctuation finished at Tc. Finally, the electron–lattice interaction was mainly elaborated to understand the superconductivity of Sr_2 CuO_(3+δ).A new low temperature Pmmm(120 K) phase was found in high temperature superconductor Sr_2 CuO_(3+δ), which was indicated as a pure electronic phase by resonant x-ray diffraction at Cu K-edge. As shown by x-ray absorption fine structure(EXAFS) and x-ray absorption near edge structure(XANES) at Cu K-edge, the strong charge density redistribution and local lattice fluctuations around Cu site at the onset of phase transition were due to the occurrence of superconductive coherence, the redistribution and fluctuation finished at Tc. Finally, the electron–lattice interaction was mainly elaborated to understand the superconductivity of Sr_2 CuO_(3+δ).

关 键 词：resonant X-RAY diffraction X-RAY absorption fine structure MODULATED phase SUPERCONDUCTIVITY 

分 类 号：O511.3[一般工业技术—材料科学与工程]