Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 44: PhD Symposium Quantum Magnets (contributed talks)

MA 44.7: Talk

Wednesday, March 22, 2017, 16:45–17:00, HSZ 403

Designing Kitaev spin liquids in metal-organic frameworks — •Masahiko G. Yamada, Hiroyuki Fujita, and Masaki Oshikawa — Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan

Kitaev’s honeycomb lattice spin model is a remarkable exactly solvable model, which has a particular type of spin liquid as the ground state, which we call Kitaev spin liquid. Although its possible realization in iridates and α-RuCl₃ has been vigorously discussed recently, these materials have substantial non-Kitaev direct exchange interactions and do not show a spin liquid ground state. We theoretically propose new metal-organic frameworks (MOFs) with Ru³⁺ (or Os³⁺) forming the honeycomb lattice as promising candidates for a more ideal realization of Kitaev-type spin models where the direct exchange interaction is strongly suppressed. The great flexibility of MOFs allows generalization to other three-dimensional lattices, for potential realization of a variety of spin liquids, including Weyl spin liquids. We argue that, in this class of materials, the degeneracy of the highest occupied molecular orbitals of the organic ligand implies a suppression of non-Kitaev interactions. As concrete examples, we estimate interactions in MOFs with oxalate-based (or tetraaminopyrazine-based) ligands, and show that they are promising candidates to realize Kitaev spin liquids.