Observation of crystal electric field (CEF) excitation of a rare-earth-based FCC compound Ba2YbNbO6

The quantum spin liquid (QSL) is an exotic state of matter. The Kitaev model is exactly solvable and has QSL as a ground state. However, there are very few rare-earth-based compounds that host Kitaev exchange interaction. We have successfully synthesized an FCC compound Ba2YbNbO6, which was proposed to be a Kitaev-type material. Detailed magnetic characterization indicates no long-range magnetic ordering down to 350 mK. Thus, to elucidate the mechanism of the magnetic ground state in this material, information about CEF splitting of the Yb3+ Kramer's ion is necessary, and hence, INS experiments are mandatory.