Momentum-dependent light scattering in a two-dimensional Heisenberg antiferromagnet: Analysis of x-ray scattering data

Motivated by the achievements of the x-ray scattering technique, we analyzed the profile of the light scattering cross section R (q,ω) at a finite q in a 2D Heisenberg antiferromagnet. Previous Raman scattering studies at q=0 identified the two-magnon peak in B1g scattering geometry. We found that the B1g peak disperses downwards at a finite q, and its cross section increases, reaching its maximum at q= q0 = (0,π) and symmetry related points. In addition, the cross-section in the A1g geometry becomes nonzero at a finite q, and also displays a two-magnon peak which gains strength and disperses to larger frequencies with increasing q, and reaches its highest cross section at q0. We found that the profile of R (q0, ω) is equivalent in A1g and B1g geometries.