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Raising Bi-O Bands Above The Fermi Energy Level Of Hole-Doped Bi₂Sr₂Cacu₂O₈+Δ And Other Cuprate Superconductors, Hsin Lin, S. Sahrakorpi, R. S. Markiewicz, A. Bansil
Raising Bi-O Bands Above The Fermi Energy Level Of Hole-Doped Bi₂Sr₂Cacu₂O₈+Δ And Other Cuprate Superconductors, Hsin Lin, S. Sahrakorpi, R. S. Markiewicz, A. Bansil
Hsin Lin
The Fermi surface (FS) of Bi₂Sr₂CaCu₂O₈₊δ (Bi2212) predicted by band theory displays Bi-related pockets around the (π,0) point, which have never been observed experimentally. We show that when the effects of hole doping either by substituting Pb for Bi or by adding excess O in Bi2212 are included, the Bi-O bands are lifted above the Fermi energy (EF) and the resulting first-principles FS is in remarkable accord with measurements. With decreasing hole doping the Bi-O bands drop below EF and the system self-dopes below a critical hole concentration. Computations on other Bi- as well as Tl- and Hg-based compounds indicate …
Origin Of The Electron-Hole Asymmetry In The Scanning Tunneling Spectrum Of The High-Temperature Bi₂Sr₂Cacu₂O₈+Δ Superconductor, Jouko Nieminen, Hsin Lin, R. S. Markiewicz, A. Bansil
Origin Of The Electron-Hole Asymmetry In The Scanning Tunneling Spectrum Of The High-Temperature Bi₂Sr₂Cacu₂O₈+Δ Superconductor, Jouko Nieminen, Hsin Lin, R. S. Markiewicz, A. Bansil
Hsin Lin
We have developed a material specific theoretical framework for modeling scanning tunneling spectroscopy (STS) of high-temperature superconducting materials in the normal as well as the superconducting state. Results for Bi₂Sr₂CaCu₂O₈₊δ (Bi2212) show clearly that the tunneling process strongly modifies the STS spectrum from the local density of states of the dₓ2₋y2 orbital of Cu. The dominant tunneling channel to the surface Bi involves the dₓ2₋y2 orbitals of the four neighboring Cu atoms. In accord with experimental observations, the computed spectrum displays a remarkable asymmetry between the processes of electron injection and extraction, which arises from contributions of Cu dz2 and …