Intrinsic accuracy in 3-dimensional photoemission band mapping

TL;DR

This paper analyzes the fundamental limits of accuracy in 3D photoemission band mapping, highlighting intrinsic broadening effects and discussing optimization strategies for improved measurements.

Contribution

It provides a detailed physical explanation of the intrinsic accuracy limits in 3D photoemission spectroscopy and explores effects like 'ghost' peaks and peak widths.

Findings

Intrinsic broadening limits mapping accuracy

Identification of 'ghost' peaks in unoccupied bands

Strategies for optimizing experimental accuracy

Abstract

Fundamental principles of mapping 3-dimensional quasiparticle dispersions in the valence band using angle-resolved photoemission spectroscopy are discussed. Such mapping is intrinsically limited in accuracy owing to damping of the final states, resulting in equivalent broadening in the surface-perpendicular wavevector. Mechanisms of the intrinsic accuracy are discussed in depth based on a physically transparent picture involving interplay of the final- and initial-state spectral functions, and illustrated by photoemission simulations and experimental examples. Other interesting effects of 3-dimensional dispersions include 'ghost' peaks in the unoccupied valence band region and finite peak width at the Fermi level. Finally, optimization of the experiment on the intrinsic accuracy is discussed.