Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 84: Correlated Electrons: (General) Theory
TT 84.4: Vortrag
Donnerstag, 3. April 2014, 10:15–10:30, HSZ 304
The puzzle of the basis-set for realistic calculations of correlated materials: The examples of Ni-heterostructures and Cuprates — •Giorgio Sangiovanni1, Nicolaus Parragh1, Philipp Hansmann2, Stefan Hummel3, Karsten Held3, and Alessandro Toschi3 — 1Universität Würzburg — 2Ecole Polytechnique, Paris — 3Technische Universität Wien
The input for materials calculations done with dynamical mean field theory is a low-energy model defined on a small set of localized wave-functions constructed after the density functional theory step. The larger the energy window of the bands used in such a construction is, the more localized the resulting wave-functions will be. Since the assumption of a local Coulomb interaction is justified only if the orbitals of the minimal basis set considered as correlated are truly localized, the agreement with experiments is expected to improve upon including a higher number of relevant degrees of freedom. In the case of transition-metal oxides this would mean considering both the more correlated d- and the less correlated p-orbitals. In several cases, however, the agreement is surprisingly much better in the d-only case.
We have shown that the physics arising from d-only and dp models for Ni-based heterostructures is indeed very dissimilar due to a different effect of the Hund’s rule coupling in the two cases [1]. Analogous issues affect also theoretical predictions for Cuprates, for which the role of the d-p hybridization may appear at a first sight less relevant [2].
N. Parragh, et al., Phys. Rev. B 88, 195116 (2013)
P. Hansmann, et al., preprint (2013)