Angle-resolved photoemission spectroscopy from first principles

by Mr Gian Parusa (PSI/LMS)

Wednesday 26 Nov 2025, 15:00 → 16:00 Europe/Zurich

OVGA/200

Angle-resolved photoemission spectroscopy (ARPES) has been known to us as a direct tool of accessing energy dispersion relation from a crystal. A recent paradigm has shifted the role of ARPES into unveiling the hidden topology of the electronic wave function space by the help of the light-matter coupling and the external light polarization. However, these intrinsic quantities are vaguely manifested in the ARPES spectra mainly due to the inherent interference effects. Moreover, the resulting ARPES spectra are modulated not only by the many-body spectral function but also the matrix element arising from the light-matter interaction. These issues address the necessity of accurate ARPES simulation from first principles. In this talk, I will show the ab initio treatments of ARPES geometry and the photoelectron states which are done on top of a plane wave basis version of Kohn-Sham equation. These two are the ingredients of the photoemission matrix element by which the ARPES intensity is modulated. Several benchmarks are done against experimental data and a dedicated experiment, confirming the accuracy and reliability of the methodology.