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Presence of a strong spin-orbit coupling (SOC) comparable to Coulomb interaction (U) and crystal field in iridium based oxides give rise to novel properties. Especially the honeycomb lattice iridates attracted lot of attention in the context of Heisenberg-Kitaev model. Extension of this model to triangular lattice has been studied theoretically and a rich phase diagram has been proposed [1, 2]. Possible materials for the realization of Heisenberg-Kitaev model in a triangular lattice will be discussed in this talk. Materials with 5d4 electronic configuration are believed to be in a nonmagnetic ground state (J=0). An interplay between U and SOC in these materials may lead to novel magnetism called excitonic magnetism [3]. In the 2nd part of the talk, Ba2YIrO6 with 5d4 (Ir5+) electronic configuration will be discussed in the context of excitonic magnetism. References: [1] M. Becker et al., Phys. Rev. B 91, 155135 (2015) [2] A. Catuneanu et al., Phys. Rev. B 92, 165108 (2015) [3] G. Khaliullin, Phys. Rev. Lett. 111, 197201 (2013)

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Tusharkanti Dey, University of Augsburg
Seminar Room of the Institute of Physics II
Contact: T. Lorenz