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Angle-resolved photoemission spectroscopy is performed on single crystals of the single-layer high-Tc superconductor Bi(2)Sr(2-x)La(x)CuO(6+d) at optimal doping (x=0.4) in order to study in great detail the Zhang-Rice (ZR) singlet band at the Fermi level. Besides the high crystal quality the advantages of a single-layer material are the absence of bilayer effects and the distinct reduction of thermal broadening. Due to the high energy and angle resolution and, most important, due to the controlled variation of the polarization vector of the synchrotron radiation the emission from the ZR singlet band reveals a distinct fine-structure. It consists of two maxima, the first showing only weak and the second at EF extremely strong polarization dependence. However, our observation has enormous consequences for line shape analyses and the determination of pseudo gaps by photoemission.
We report the discovery of a self-doped multi-layer high Tc superconductor Ba2Ca3Cu4O8F2(F0234) which contains distinctly different superconducting gap magnitudes along its two Fermi surface(FS) sheets. While formal valence counting would imply this
The high-energy kink or the waterfall effect seen in the photoemission spectra of the cuprates is suggestive of the coupling of the quasiparticles to a high energy bosonic mode with implications for the mechanism of superconductivity. Recent experime
First-principles calculations were performed to investigate the electronic structure and the Fermi surface of the newly discovered low-temperature superconductor: fluorine-doped WO3. We find that F doping provides the transition of the insulating tun
The Nernst effect in metals is highly sensitive to two kinds of phase transition: superconductivity and density-wave order. The large positive Nernst signal observed in hole-doped high-Tc superconductors above their transition temperature Tc has so f
We have measured the low temperature heat capacity Cp and microwave surface impedance Zs in the vortex state of YNi_2B_2C. In contrast to conventional s-wave superconductors, Cp shows a nearly sqrt H-dependence. This sqrt H-dependence persists even a