A Magnon Band Analysis of GdRu2Si2 in the Field-Polarized State

Understanding the formation of skyrmions in centrosymmetric materials is a problem of fundamental and technological interest. GdRu2Si2 is one such candidate material which has been shown to host a variety of multi-Q magnetic structures, including in zero-field. Here, inelastic neutron scattering is used to measure the spin excitations in the field-polarized phase of GdRu2Si2. Linear spin wave theory and a method of interaction invariant path analysis are used to derive a Hamiltonian accounting for the observed spectra, and comparisons to \textit{ab initio} calculations are made. No evidence for anisotropic or higher order-exchange terms beyond bilinear Heisenberg exchange is found. This is discussed in the context of the multi-Q states existing at lower fields, for which these types of terms have previously been conceived to be significant in the formation of multi-Q ground states.