- Trinanjan Datta, Augusta University, Augusta, Georgia
I will present our recent findings on the effects of magnon-phonon coupling in the indirect K-edge bimagnon resonant inelastic x-ray scattering (RIXS) intensity spectrum of a square lattice Heisenberg antiferromagnet. Utilizing the Dyson-Maleev spin wave expansion up to 1/S order, the Bethe-Salpeter ladder approximation scheme for the bimagnon interacting channel, and considering the lowest order magnon-phonon-magnon scattering interaction we highlight distinct features in the RIXS spectrum for both the antiferromagnetic and the collinear antiferromagnetic phases. Considering damping effects, arising due to the presence of phonons, we find that in the antiferromagnetic phase the RIXS intensity spectrum attains a maximum value primarily localized around the K-point. For the collinear phase the intensity is broadly distributed with a significant scattering intensity located around the Y-point. In the collinear phase for suitable anisotropy, nearest-, and next-nearest neighbor interaction parameters the phonon effects can manifest itself as a distinct peak both below and above the bimagnon peak. Such a feature is in contrast to the antiferromagnetic spectrum where the effect due to the phonon peak was located consistently beyond the bimagnon peak in the high energy end of the spectrum. We conclude that magnon-phonon effects in the indirect K-edge RIXS spectrum, in both the antiferromagnetic and the collinear antiferromagnetic phase, is an observable effect.