Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Frustrated Magnets - Pyrochlore Systems and Iridates
TT 3.8: Vortrag
Montag, 7. März 2016, 11:30–11:45, H20
Metal-insulator transition of pyrochlore iridates and their topological properties — •Hongbin Zhang1,2, Kristjan Haule2, and David Vanderbilt2 — 1Materialwissenschaft, TU Darmstadt Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany — 2Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, NJ-08854, USA
The interplay of spin-orbit coupling and electronic correlations can lead to many fascinating physical properties, where iridates are a promising playground. Combining density functional theory (DFT) and embedded dynamical mean-field theory (DMFT) methods, we study the metal-insulator transition in R2Ir2O7 (R=Y, Eu, Sm, Nd, Pr, and Bi) and the topological nature of the insulating compounds. Accurate free energies evaluated using the charge self-consistent DFT+DMFT method reveal that the metal-insulator transition occurs for an A-cation radius between that of Nd and Pr, in agreement with experiments. The all-in-all-out magnetic phase, which is stable in the Nd compound but not the Pr one, gives rise to a small Ir4+ magnetic moment of ≈ 0.5µB and opens a sizable correlated gap. We demonstrate that within this state-of-the-art theoretical method, the insulating bulk pyrochlore iridates are topologically trivial.