Electronic and magnetic Raman scattering in correlated electron system

Raman scattering is a very sensitive and effective probe for measuring lattice vibrations in periodic structures and the vibrations or rotations of molecules; the spectra obtained are considered the fingerprint of a specific substance. Today, Raman spectroscopy is extensively employed in fundamental research and industry. In principle, one can also obtain valuable information about electronic and magnetic excitations from the process of inelastic light scattering by free carriers or spins in a solid. This paper gives a brief review of the basic concepts and experiments on electronic and magnetic Raman scattering in various correlated electron systems, especially in unconventional superconductors where the superconducting gap size，anisotropy, and pairing symmetry can be uniquely determined by Raman spectroscopy.