Spin liquid like Raman signatures in hyperkagome iridate   Na$_4$Ir$_3$O$_8$
  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 Na$_4$Ir$_3$O$_8$. In the measurements we observe a broad Raman band at $\sim$~3500 cm$^{-1}$ with a band-width $\sim 1700$~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 ($J_K$) is much larger than the Heisenberg term J$_1$ ($J_1/J_K \sim 0.1$). A comparison with the theoretical model gives an estimate of the Kitaev exchange interaction parameter. 
Satyendra Nath Gupta, P. V. Sriluckshmy, Ashiwini Balodhi, D. V. S.   Muthu, S. R. Hassan, Yogesh Singh, T. V. Ramakrishnan ...
cond-mat.str-el