Observing two-electron interactions with correlation-ARPES
Phys. Rev. B 112, 035168 – Published 28 July, 2025
DOI: https://doi.org/10.1103/4fqm-z742
Abstract
Identifying and studying the underlying two-electron interactions that give rise to emergent phenomena is a key step in developing a holistic understanding of quantum materials. This step is hindered by the lack of an experiment that can directly interrogate the interactions and the specific quasiparticles involved in the interaction simultaneously. We introduce correlation-ARPES as an experimental method that overcomes this difficulty and directly measures the interactions between specific, chosen quasiparticles by measuring the correlations between two electrons photoemitted from the same pulse (but not the same photon). We illustrate how this technique can extract the underlying interactions and demonstrate this with an example of phonon-mediated electron-electron interactions, such as those that give rise to charge density waves through the Kohn anomaly mechanism.
