Spin dynamics in a new hyperhoneycomb antiferromagnet

This proposal is part of our research programme to explore novel ground states stabilized by frustrated interactions in quantum magnets. Here we plan to measure the spin dynamics in a novel Pr hyperhoneycomb lattice antiferromagnet, that we have recently succeeded in synthesizing for the first time. The hyperhoneycomb lattice has three-coordination as the planar honeycomb, but bond rotations make it a fully three-dimensional network. Strong spin-orbit coupling at the 4f Pr4+ ions with jeff=1/2 inside edge-shared oxygen octahedra arranged on a hyperhoneycomb lattice are predicted to lead to strongly-frustrated (Kitaev) interactions that could potentially stabilize an exotic quantum spin liquid with fractionalized spinon excitations. To explore such ideas and find the relevant interactions, we propose to measure the spin excitations using LET.