Spin dynamics and crystal field transitions of FCC frustrated quantum antiferromagnets

This proposal is part of our research programme to explore frustrated magnetism in the presence of strong spin orbit coupling. We have recently synthesized double pervoskites based on Yb3+ ion, which are candidates to display strong frustration effects on a face-centred cubic lattice. Theoretical proposals have been put forward that the strong spin-orbit coupling could stabilize bond-dependent anisotropic interactions, similar to Kitaev exchange in spin-orbit coupled honeycomb iridates. Here we plan to determine the crystal field transitions and thus deduce the magnetic ground state of the Yb3+ ions, and probe also the spin excitations and search for quantum zero-point gaps.