Deconstruction of resolution effects in angle-resolved photoemission

Abstract

We study how the energy and momentum resolution of angle-resolved photoemission spectroscopy (ARPES) affects the linewidth, Fermi crossing, velocity, and curvature of the measured band structure. Based on the fact that the resolution smooths out the spectra, acting as a low-pass filter, we develop an iterative simulation scheme that compensates for resolution effects and allows the fundamental physical parameters to be accurately extracted. By simulating a parabolic band structure of Fermi-liquid quasiparticles, we show that this method works for an energy resolution up to 100 meV and a momentum resolution equal to twice the energy resolution scaled by the Fermi velocity. Our analysis acquires particular relevance in the hard and soft x-ray regimes, where a degraded resolution limits the accuracy of the extracted physical parameters, making it possible to study how the electronic excitations are modified when the ARPES probing depth increases beyond the surface.