Angle resolved photoelectron spectroscopy: From traditional to two‐dimensional photoelectron spectroscopy

Overview of core and valence photoemission

“…Thus, it is the many-body excitation spectrum which is hidden in the photoelectron spectral distribution. Investigations have made significant progress toward this goal, including analyses of the many-body spectral density, of the Fermi-liquid type or the shape of the Fermi surface [21,94], of the intrinsic and extrinsic inelastic losses by plasmon shake-offs [49], and of magnetic excitations [55]. The momentum resolved gap in semiconductors hides manybody effects, and is an experimental quantity that can be extremely carefully determined by photoemission.…”