Combining Raman scattering measurements with mean field calculations of the Raman response we show that Kitaev-like magnetic exchange is dominant in the hyperkagome iridate Na4Ir3O8. In the measurements we observe a broad Raman band at ∼~3500 cm−1 with a band-width ∼1700~cm−1. Calculations of the Raman response of the Kitaev-Heisenberg model on the hyperkagome lattice shows that the experimental observations are consistent with calculated Raman response where Kitaev exchange interaction (JK) is much larger than the Heisenberg term J1 (J1/JK∼0.1). A comparison with the theoretical model gives an estimate of the Kitaev exchange interaction parameter.
@article{arxiv.1606.07938,
title = {Spin liquid like Raman signatures in hyperkagome iridate Na$_4$Ir$_3$O$_8$},
author = {Satyendra Nath Gupta and P. V. Sriluckshmy and Ashiwini Balodhi and D. V. S. Muthu and S. R. Hassan and Yogesh Singh and T. V. Ramakrishnan and A. K. Sood},
journal= {arXiv preprint arXiv:1606.07938},
year = {2016}
}