Development of 2e-ARPES to Measure Correlated Electron Pairs in Unconventional Superconductors II

Elucidating the nature of electronic correlations, intertwined orders, and pairing symmetries in unconventional superconductors is one of the main challenges in modern condensed matter physics. Here we present our group's recent development of two electron coincidence photoemission spectroscopy (2e-ARPES) as a promising platform to probe the properties of finite-momentum pairing states in superconductors, such as the pair center-of-mass momentum as well as the spin state of Cooper pairs. In this talk, we will specifically present our experimental realization of 2e-ARPES by means of two time-of flight photoelectron analyzers, a hardware timing circuit, and a post-processing algorithm to identify true coincident detection events. We will also share some preliminary 2e-ARPES data in various unconventional superconductors.