Dipole-quadrupole spherical tensors in resonant x-ray diffraction
Résumé
Parity-breaking phenomena in condensed-matter physics, either associated or not to time-reversal-breaking effects, are nowadays considered as an important part of fundamental and applied research, especially in connection to multiferroic materials. Resonant x-ray diffraction is probably the most suited experimental technique to study multiferroic order parameters. In the present note, after some introduction on multipolar order parameters, I provide the polarization and wave-vector dependence of the spherical tensors involved in parity-breaking effects in resonant x-ray diffraction.