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One‐Step Model of Photoemission for Nonlocal Potentials
Author(s) -
Potthoff M.,
Lachnitt J.,
Nolting W.,
Braun J.
Publication year - 1997
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(199710)203:2<441::aid-pssb441>3.0.co;2-7
Subject(s) - wave function , electronic band structure , generalization , dipole , physics , electronic structure , valence (chemistry) , scattering , quantum mechanics , condensed matter physics , mathematical analysis , mathematics
The one‐step model of valence‐band photoemission and inverse photoemission from single‐crystal surfaces is reformulated for generalized (nonlocal, complex and energy‐dependent) potentials. Thereby, it becomes possible to account for self‐energy corrections taken from many‐body electronic‐structure calculations. The original formulation due to Pendry and coworkers employs the KKR multiple‐scattering theory for the calculation of the initial state. This prevents a straightforward generalization of the one‐step model to nonlocal potentials. We therefore consider the Dyson equation which is set up within a muffin‐tin‐orbital representation as an alternative to obtain the initial‐state Green function. This approach requires a revision of the transition‐matrix elements which is carried out in detail. The final state is considered as a time‐reversed LEED state as usual. The proposed generalization of the one‐step model allows to distinguish between the bare photocurrent reflecting the (quasi‐particle) band structure and the secondary effects due to the (dipole) selection rules and due to the wave‐vector and energy dependence of the transition‐matrix elements.