Angle-resolved photoemission intensity for multiorbital bands: Complex interplay between the self-energy matrix and the optical matrix elements
Phys. Rev. B 112, 115127 – Published 12 September, 2025
DOI: https://doi.org/10.1103/dtg3-66t9
Abstract
We use a simple one-dimensional two-band model with electron-phonon coupling to illustrate some of the complications that arise in multiband systems when trying to extract a self-energy using the typical approach used for single-band systems when analyzing angle-resolved photoemission spectroscopy (ARPES) data. The underlying reason is that in multiband models, the self-energy is a matrix, not a scalar, and the result obtained from the ARPES analysis is a complicated function of all these self-energy matrix elements, weighted by different dipole matrix elements of the relevant Wannier orbitals. We contrast the results for Holstein and Peierls electron-phonon couplings to further illustrate differences between models with a local versus nonlocal self-energy matrix.
