We synthesize and study single crystals of the layered honeycomb lattice Mott insulators Na2RuO3 and Li2RuO3 with magnetic Ru4+(4d4) ions. The newly found Na2RuO3 features a nearly ideal honeycomb lattice and orders antiferromagnetically at 30 K. Single crystals of Li2RuO3 adopt a honeycomb lattice with either C2/m or more distorted P21/m below 300 K, depending on detailed synthesis conditions. We find that Li2RuO3 in both structures hosts a well-defined magnetic state, in contrast to the singlet ground state found in polycrystalline Li2RuO3. A phase diagram generated based on our results uncovers a new, direct correlation between the magnetic ground state and basal-plane distortions in the honeycomb ruthenates.
Digital Object Identifier (DOI)
This work was supported by the National Science Foundation via Grants No. DMR-0856234, No. DMR-1265162, and No. DMR-1056536 (R.K.K.), Russian Science Foundation via RSCF Grant No. 14-22-00004 (S.V.S.), German project FOR 1346, Cologne University via German excellence initiative (D.K.), DOE BES Office of Scientific User Facilities (F.Y.), and China Scholarship Council (J.C.W.).
Wang, J. C.; Terzic, Jsaminka; Qi, T. F.; Ye, Feng; Yuan, Shujuan; Aswartham, Saicharan; Streltsov, S. V.; Khomskii, D. I.; Kaul, Ribku K.; and Cao, Gang, "Lattice-Tuned Magnetism of Ru4+(4d4) Ions in Single Crystals of the Layered Honeycomb Ruthenates Li2RuO3 and Na2RuO3" (2014). Physics and Astronomy Faculty Publications. 301.