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)
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 absorp...