Stripe structure in the CuO2 plane of perovskite superconductors.

摘要: The Cu-O pair-distribution function in a ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathit{y}}$ superconductor has been measured by polarized Cu K-edge extended x-ray-absorption fine structure at T${\mathit{T}}_{\mathit{c}}$. results show an anomalous long (planar) distance, 1.96 \AA{}, assigned to distorted ${\mathrm{CuO}}_{2}$ stripes of width W intercalated with undistorted L. From the measurement L=15\ifmmode\pm\else\textpm\fi{}0.5 \AA{} we have calculated energies ${\mathit{E}}_{\mathit{n}}$ bottom one-dimensional subbands superlattice and found that Fermi level ${\mathit{E}}_{\mathit{F}}$ is tuned ``shape resonance'' ${\mathit{E}}_{\mathit{F}}$-${\mathit{E}}_{\mathit{n}}$${\mathrm{\ensuremath{\omega}}}_{\mathit{D}}$, where ${\mathrm{\ensuremath{\omega}}}_{\mathit{D}}$ Debye frequency, giving ${\mathit{T}}_{\mathit{c}}$ amplification. \textcopyright{} 1996 American Physical Society.