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TT: Fachverband Tiefe Temperaturen

TT 86: Correlated Electrons: Other Materials

TT 86.7: Vortrag

Donnerstag, 3. April 2014, 11:15–11:30, BEY 81

Fermi surface of Sr_n+1Ru_nO_3n−1 ruthenates: LDA+DMFT study — •Evgeny Gorelov, Guoren Zhang, and Eva Pavarini — IAS, Forschungszentrum Jülich, 52425 Jülich

The layered ruthenates of the Ruddlesden-Popper family Sr_n+1Ru_nO_3n+1 are interesting examples of strongly correlated transition metal compounds. Because kinetic and Coulomb energy are of the same order for Ru 4d electrons, these compounds have a very rich phase diagram. Furthermore, the spin-orbit coupling (SOC) is comparable with crystal-field splitting of t_2g levels and it is thus crucial for the description of the Fermi surface.

In the present work we focus on three compounds of the Sr_n+1Ru_nO_3n+1 family: single-layered Sr₂RuO₄, double layered Sr₃Ru₂O₇, and triple-layered Sr₄Ru₃O₁₀. We study the shape of the Fermi surface and the electron mass renormalization in the presence of correlation effects and SOC. In our LDA+DMFT (local-density approximation + dynamical mean-field theory) scheme we use maximally-localized Wannier orbitals obtained from Linearized Augmented Plane Wave (LAPW) ab-initio calculations to build a low-energy Hubbard model for the Ru 4d bands; we use the weak-coupling quantum Monte Carlo method to solve the quantum impurity problem. We take into account the full rotationally-invariant Coulomb interaction, as well as full on-site self-energy matrix in spin-orbital space. For Sr₄Ru₃O₁₀ we use the cluster DMFT scheme to account for the inequivalent Ru atoms.