Due to the combination of a substantial spin-orbit coupling and correlation effects, iridium oxides hold a prominent place in the search for novel quantum states of matter, including, e.g., Kitaev spin liquids and topological Weyl states. We establish the promise of the very recently synthesized hyper-honeycomb iridate β-Li2IrO3 in this regard. A detailed theoretical analysis reveals the presence of large ferromagnetic first-neighbor Kitaev interactions, while a second-neighbor antiferromagnetic Heisenberg exchange drives the ground state from ferro to zigzag order via a three-dimensional Kitaev spin liquid and an incommensurate phase. Experiment puts the system in the latter regime but the Kitaev spin liquid is very close and reachable by a slight modification of the ratio between the second- and first-neighbor couplings, for instance via strain.
@article{arxiv.1603.04003,
title = {The vicinity of hyper-honeycomb $\beta$-Li2IrO3 to a three-dimensional Kitaev spin liquid state},
author = {Vamshi M. Katukuri and Ravi Yadav and Liviu Hozoi and Satoshi Nishimoto and Jeroen van den Brink},
journal= {arXiv preprint arXiv:1603.04003},
year = {2017}
}