Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 8: Postersitzung I: Supraleitung
TT 8.49: Poster
Montag, 8. März 2004, 14:30–19:00, Poster A
Pressure and Doping Dependence of the Super Exchange of 2D-Cuprates — •Helge Rosner1, Ulrike Nitzsche2, and Stefan-Ludwig Drechsler2 — 1Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Str. 40, D-01187 Dresden, Germany — 2Leibniz Institute for Solid State and Materials Research Dresden, P.O.B. 270016, 01171 Dresden, Germany
The dependence of superconducting Tc from the exchange integrals J is investigated within many models devoted to HTSC. However, most of these models ignore the dependence of the exchange integrals on both the lattice parameters and the doping level because of lacking reliable data. Here we present a systematic study for the two-dimensional model compound CaCuO2. Based on LDA and LDA+U band structure calculations and subsequently derived tight-binding models we calculate the magnitude of the most relevant exchange integrals and their dependence on doping and uniaxial pressure. We compare the results of total energy calculations with those of various tight-binding models (one-band and multi-band approaches) and the parameters obtained by microscopic models analyzing the experimental data for the superconducting HgBaCuO-family.