TUNING OF THE FERMI-LEVEL AT THE 2ND SUBBAND OF A SUPERLATTICE OF QUANTUM WIRES IN THE CUO2 PLANE - A POSSIBLE MECHANISM TO RAISE THE CRITICAL-TEMPERATURE

The structure of the stripes in Bi2Sr2CaCu2O8+y superconductor has bee n refined by polarized Cu K-edge extended X-ray absorption fine struct ure (EXAFS). The distribution of Cu-O (planar) distances range from 1. 87 Angstrom to 1.96 Angstrom. The results show that the in-plane CuO2 lattice distortions in the 1D modulation are large enough to form a po tential barrier of width W between the stripes of undistorted CuO2 lat tice of width L = 15 +/- 0.5 Angstrom. The calculations show that the maximum of the density of states formed by the second subband is tuned to the Fermi level.