Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
MA 33.5: Vortrag
Mittwoch, 18. März 2020, 10:30–10:45, HSZ 403
Competition of Hund’s and spin-orbit couplings in cubic d4 halides — •Alexander Yaresko1, Hiroto Takahashi1,2, and Hidenori Takagi1,2,3 — 1Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany — 2Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 133-0022, Japan — 3Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
In transition metal compounds with more than one d-electron or hole Hund’s coupling JH and pin-orbit coupling ξ compete. The competition manifests itself in the contrast between the LS-coupling and the jj-coupling schemes in the large JH and large ξ limits, respectively. Cubic double-perovskite-like K2RuCl6 and K2OsCl6 compounds with t2g4 Ru4+ and Os4+ at the center of a regular Cl6 octahedron are expected to be non-magnetic Jeff = 0 Mott insulators; with the former being closer to the LS- and the latter to the jj-coupling limit. We performed LDA+U calculations using JH as a tunable parameter which reveal that a transition from a non-magnetic to magnetic insulating ground state is controlled by the ratio JH/ξ. With realistic parameters of JH, K2RuCl6 is placed in the LS-coupling regime and K2OsCl6 is at the border between the two schemes.