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TT: Fachverband Tiefe Temperaturen

TT 68: Correlated Electrons: (General) Theory 1

TT 68.2: Vortrag

Mittwoch, 18. März 2015, 15:15–15:30, H 3010

La₂NiTiO₆: A 3D S=1 fcc Heisenberg antiferromagnet — Michael Karolak, •Martin Edelmann, and Giorgio Sangiovanni — Institut für Theoretische Physik und Astrophysik, Universität Würzburg

The double perovskite La₂NiTiO₆ is identified as an interesting S=1 quantum antiferromagnet on a three-dimensional fcc sublattice. By means of Density Functional Theory (DFT) in combination with Dynamical Mean Field Theory (DMFT) it is demonstrated that this material is a high-spin d-electron system deep in the Heisenberg limit and established that its paramagnetic Mott phase persists down to low temperatures not because of frustration effects but rather for the strong coupling physics. The strong-coupling nature is assessed from a multi-orbital DFT+DMFT analysis of the energetic balance between the ordered and disordered phase, which reveals a kinetic-energy-driven ordering. La₂NiTiO₆ emerges thus as a paradigmatic realization of a spin-triplet Mott insulator[1].

[1] M. Karolak, M. Edelmann, and G. Sangiovanni,

arXiv:1407.2255 (2014).