Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 24: Low-Dimensional Systems: 1D - Theory
TT 24.12: Vortrag
Dienstag, 21. März 2017, 12:30–12:45, HSZ 204
Role of Cu 4d and O 3p orbitals in the many-body wavefunction of corner-sharing cuprates — •Nikolay A. Bogdanov1, Giovanni Li Manni1, Sandeep Sharma1, Olle Gunnarsson1, and Ali Alavi1,2 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2University Chemical Laboratory, Cambridge, U.K.
Electronic and magnetic properties of one- and two-dimensional cuprates have been investigated for several decades but are still not fully understood. We study the electronic structure of the undoped Sr2CuO3 and La2CuO4 corner-sharing cuprates with state-of-the-art wavefunction-based ab initio calculations. We find that in order to obtain reasonable agreement with the experimentally observed large magnetic exchange couplings for these compounds, it is necessary to go beyond multiband models containing only Cu 3d and O 2p bands. To capture the orbital breathing effects it is necessary to extend the model space with diffuse Cu 4d and O 3p orbitals. For a Cu-O-Cu unit this leads to a problem of 24 electrons in 26 orbitals that can’t be solved with conventional methods. In our study we employ full configuration interaction quantum Monte Carlo (FCIQMC) and density matrix renormalization group (DMRG) techniques to tackle this problem.