Coulomb shift of the photoemission threshold in crystals
Volkov B. A. , Sharov S. V.
It is pointed out that in most metals the threshold energy for photoemis-sion is lower than the ionization energy of the isolated constituent atoms of the metal. A similar effect has also been observed in semiconductors. An interpretation of this phenomenon is proposed on the basis of the electron-electron Coulomb interaction and derealization of electrons in a crystal. It is shown on the basis of the model of a metal consisting of monovalent atoms that the shift of the photoemission threshold is determined by the matrix element of the intra-atomic Coulomb interaction of the electrons with different spin orientations. The connection between the effect and the metal-Mott-Hubbard insulator transition is discussed. © 1995 American Institute of Physics.