From a Homogeneous CuO2 Plane to a Superlattice of Quantum Stripes

Joint analysis of polarized Cu K-edge extended x-ray absorption fine structure (EXAFS) and Cu K-edge anomalous x-ray diffraction have shown that the modulated structure of the CuO2 plane in Bi2Sr2CaCu2O8+y (Bi2212) superconductor is made of a superlattice of quantum stripes. At optimum doping the Fermi level EF is tuned to a “shape resonance” EF-Ensuperlattice of quantum stripes with a finite ID periodic potential barrier has been calculated using the experimental parameters for Bi2212 system and a resonant enhancement of the superconducting gap is found.