Abstract
Abstract EXAFS experiments on La2-x,SrxCuO4 (LSCO) have revealed that the Sr dopants occupy two kinds of sites, a magnetic Cu one with long Sr-apical O bonds, and a metallic Cu one with short Sr-apical O bonds. Very surprisingly, the fraction of metallic bonds decreases as x−0.9 through the insulator-metal transition, which takes place in two stages. Homogeneous high-temperature superconductivity occurs only in the intermediate phase between these two transitions. The author's earlier filamentary theories of the impurity band (Sip) and cuprate (YBCO) metal-insulator transitions are extended to discuss the phase diagrams of pseudogaps and superconductivity in LSCO in the light of the EXAFS data. Differences between LSCO and YBCO are also explained naturally by differences in nanodomain structures. The recent observation of superconductivity in ferromagnetic RuSr2GdCu2O8−δ, with a T c similar to that of LSCO, is explained without additional assumptions by the filamentary theory.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
