Photoemission spectroscopy and sum rules in dilute electronphonon systems
Abstract
A family of exact sum rules for the onepolaron spectral function in the lowdensity limit is derived. An algorithm to calculate energy moments of arbitrary order of the spectral function is presented. Explicit expressions are given for the first two moments of a model with general electronphonon interaction, and for the first four moments of the Holstein polaron. The sum rules are linked to experiments on momentumresolved photoemission spectroscopy. The bare electronic dispersion and the electronphonon coupling constant can be extracted from the first and second moments of the spectrum. The sum rules could serve as constraints in analytical and numerical studies of electronphonon models.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 September 2002
 DOI:
 10.1209/epl/i200200187x
 arXiv:
 arXiv:condmat/0202186
 Bibcode:
 2002EL.....59..735K
 Keywords:

 71.38.k;
 79.60.i;
 Polarons and electronphonon interactions;
 Photoemission and photoelectron spectra;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 4 pages