Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.22: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Exchange integrals in 1D versus 2D cuprates - an electronic structure study — •Ulrike Nitzsche1, Stefan-Ludwig Drechsler1, and Helge Rosner2 — 1Leibniz Institute for Solid State and Materials Research Dresden — 2MPI for Chemical Physics of Solids
We present a systematic study of the electronic structure and the exchange integrals for different types of 1D and 2D cuprate networks: edge and corner shared single-chain (Li2CuO2, Sr2CuO3), double-chain (SrCuO2), ladder-type (Sr2Cu2O3) and planar (CaCuO2, Sr2CuO2Cl2) arrangements. Based on full potential LSDA and LSDA+U band structure calculations and subsequently derived tight-binding models we estimate sign and magnitude of the most relevant exchange integrals. We compare the results of total energy calculations with those of various tight-binding models from one-band and multi-band approaches. We investigate the effect of the network configuration (edge shared vs. corner shared CuO2 plaquettes) and of the dimensionality on the coupling strength. The influence of external parameters like pressure and doping is briefly discussed.