Roton like dipsersion in the chiral compound CrNb3S6

Chirality is traditionally described as the breaking of parity symmetry in static objects. This concept has since been extended to include the dynamics of quasi-particles, such as phonons. Recently, there has been increasing attention on phonons with chirality, known as chiral phonons. In this proposal, we aim to investigate chiral phonons in CrNb3S6 for the first time. Theoretical studies suggest that the lowest transverse acoustic (TA) branch displays a roton-like minimum, similar to the excitation spectrum of superfluid helium-4. We are requesting four days of experimental time on ID28 to study the TA chiral mode of CrNb3S6 using its high energy resolution.