2006/07/31 by Wenhui Xie, O. Jepsen, O. K. Andersen +3 · 1 citation
Engineering · Physics and Astronomy · #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity in MgB2 and Alloys #cond-mat.dis-nn #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.98.047001
4 pages, 3 figures
arxiv created 2006/08/30 · openalex publication_date 2007/01/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
An undoped cuprate with apical fluorine and inner (i) and outer (o) CuO(2) layers is a 60 K superconductor whose Fermi surface has large n- and p-doped sheets with the superconducting gap on the n sheet twice that on the p sheet. The Fermi surface is not reproduced by the local density approximation, but the screening must be substantially reduced due to electronic correlations, and oxygen in the o layers must be allowed to dimple outwards. This charges the i layers by 0.01|e|, causes a 0.4 eV Madelung-potential difference between the i and o layers, quenches the i-o hopping, and localizes the n sheets onto the i layers, thus protecting their d-wave pairs from being broken by scattering on impurities in the BaF layers. The correlation-reduced screening strengthens the coupling to z-axis phonons.