*

Magnetic skyrmion crystals are traditionally associated with non-centrosymmetric crystal structures; however, it has been demonstrated that skyrmion crystals can be stabilized by competing interactions in centrosymmetric crystals [1]. To understand and optimize the physical responses associated with topologically-nontrivial skyrmion textures, it is important to quantify their magnetic interactions by comparing theoretical predictions with spectroscopic data. Here, we present neutron diffraction and spectroscopy data on the centrosymmetric skyrmion material GdRu₂Si₂ [2,3], and show that the key spectroscopic features can be explained by the magnetic interactions obtained using density-functional theory calculations [4]. We further discuss how the agreement with our experimental data differs between the initially-proposed helical ground state and the double-q "topological charge stripe" ground state determined experimentally [5], and how the magnetic structure evolves with temperature.

[1] Okubo et al., Phys. Rev. Lett. 108, 017206 (2012); [2] Yasui et al., Nat. Commun. 11, 5925 (2020); [3] Khanh et al., Nat. Nanotech. 15, 444-449 (2020); [4] Bouaziz et al., Phys. Rev. Lett. 128, 157206 (2022); [5] Wood et al., Phys. Rev. B 107, L180402 (2023).