Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates

TT 3.7: Vortrag

Montag, 7. März 2016, 11:15–11:30, H20

First-principles study of strong correlation effects in pyrochlore iridates — •Hiroshi Shinaoka¹, Shintaro Hoshino², Matthias Troyer³, and Philipp Werner⁴ — ¹Department of Physics, Saitama University, Japan — ²Department of Basic Science, The University of Tokyo, Japan — ³Theoretische Physik, ETH Zuerich, Switzerland — ⁴Department of Physics, University of Fribourg, Switzerland

The pyrochlore iridates A₂Ir₂O₇ (A=Pr, Nd, Y, etc.) are an ideal system to study fascinating phenomena induced by strong electron correlations and spin-orbit coupling. In this talk, we study strong correlation effects in the prototype compound Y₂Ir₂O₇ using the local density approximation and dynamical mean-field theory (LDA+DMFT) [1]. We map out the phase diagram in the space of temperature, onsite Coulomb repulsion U, and filling. Consistent with experiments, we find that an all-in/all-out ordered insulating phase is stable for realistic values of U. We reveal the importance of the hybridization between j_eff = 1/2 and j_eff = 3/2 states under the Coulomb interaction and trigonal crystal field. We demonstrate a substantial band narrowing in the paramagnetic metallic phase and non-Fermi liquid behavior in the electron/hole doped system originating from long-lived quasi-spin moments induced by nearly flat bands. We further compare our results with recent experimental results of Eu₂Ir₂O₇ under hydrostatic pressure [2].
H. Shinaoka, S. Hoshino, M. Troyer, P. Werner,

PRL 115, 156401 (2015)
G. Prando, R. Dally, W. Schottenhamel, Z. Guguchia, S.-H. Baek,

R. Aeschlimann, A. U. B. Wolter, S. D. Wilson, B. Büchner,

M. J. Graf, arXiv:1511.03037