Realization of a three-dimensional spin-anisotropic harmonic honeycomb iridate. by Modic, K, Smidt, T, Kimchi, I, Breznay, N, Biffin, A, Choi, S, Johnson, R, Coldea, R, Watkins-Curry, P, McCandless, G, Chan, J, Gandara, F, Islam, Z, Vishwanath, A, Shekhter, A, McDonald, R, Analytis, J