We report the successful synthesis of single-crystals of the layered iridate, (Na1−xLix)2IrO3, 0≤x≤0.9, and a thorough study of its structural, magnetic, thermal and transport properties. The new compound allows a controlled interpolation between Na2IrO3 and Li2IrO3, while maintaing the novel quantum magnetism of the honeycomb Ir4+ planes. The measured phase diagram demonstrates a dramatic suppression of the N\'eel temperature, TN, at intermediate x suggesting that the magnetic order in Na2IrO3 and Li2IrO3 are distinct, and that at x≈0.7, the compound is close to a magnetically disordered phase that has been sought after in Na2IrO3 and Li2IrO3. By analyzing our magnetic data with a simple theoretical model we also show that the trigonal splitting, on the Ir4+ ions changes sign from Na2IrO3 and Li2IrO3, and the honeycomb iridates are in the strong spin-orbit coupling regime, controlled by \jeff=1/2 moments.
@article{arxiv.1307.2212,
title = {Evolution of Magnetism in Single-Crystal Honeycomb Iridates},
author = {G. Cao and T. F. Qi and L. Li and J. Terzic and V. S. Cao and S. J. Yuan and M. Tovar and G. Murthy and R. K. Kaul},
journal= {arXiv preprint arXiv:1307.2212},
year = {2014}
}