cond-mat.str-el

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# Title:Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3

Abstract: In quantum magnetism spin dimers are typically associated with spin-singlet states. To date, $triplet$ $dimerization$ has not been observed in any 3D or quasi-2D material. With this in mind we here discuss the electronic structure of the spin-orbit driven $5d^5$ Mott insulator Li$_2$IrO$_3$, a honeycomb-lattice system with two crystallographically inequivalent Ir-Ir bonds. From $ab$ $initio$ many-body calculations we find that, while both Heisenberg and Kitaev couplings are present, the magnetic interactions are dominated by a strong isotropic ferromagnetic exchange on only one set of bonds. This causes the formation of triplet spin dimers effectively placed on a strongly frustrated triangular lattice. The triplet dimers remain protected in a large region of the phase diagram, suggesting that Li$_2$IrO$_3$ has a long-range incommensurate magnetic ground state that is pushed by the Kitaev exchange interactions beyond a standard planar helix configuration.
 Comments: 5 pages, 3 figures, revised from the previous version Subjects: Strongly Correlated Electrons (cond-mat.str-el) Journal reference: Nat. Commun. 7:10273 (2016) DOI: 10.1038/ncomms10273 Cite as: arXiv:1403.6698 [cond-mat.str-el] (or arXiv:1403.6698v2 [cond-mat.str-el] for this version)

## Submission history

From: Vamshi Mohan Katukuri [view email]
[v1] Wed, 26 Mar 2014 14:43:29 UTC (1,023 KB)
[v2] Thu, 26 Nov 2015 09:23:38 UTC (1,700 KB)