Two-electron ARPES
The two-electron ARPES (2e-ARPES) platform is a new coincidence photoemission facility currently under construction, being developed jointly by our group and David Jones’ group. It is being built around a NanoESCA MARIS momentum microscope with time-of-flight capability and a HEX75 multi-hit delay-line detector, integrated in a dedicated ultra-high-vacuum system with fast-entry load lock, LHe-cooled 6-axis hexapod manipulator, and equilibrium VUV and UV light sources for sample alignment and conventional electronic-structure characterization. The instrument combines real-space and momentum-space imaging with aberration-compensated twin-hemisphere energy filtering, allowing users to zoom in both real and momentum space and to investigate microscale samples under ultra-high-vacuum conditions.
The system is also being designed for integration with a femtosecond XUV laser source of the same family used in the Moore facility, operating at 60 MHz and providing the high photon energies required for coincidence photoemission. In this configuration, the platform is intended for momentum- and energy-resolved detection of two electrons simultaneously photoemitted from correlated many-body states, with target performance in the 15-20 meV energy-resolution range and 150-190 fs time-resolution range. Once operational, it will extend photoemission from the single-particle to the two-particle level, with a particular focus on directly probing Cooper-pair correlations in conventional and unconventional superconductors, in close connection with ongoing theoretical work on the two-particle photoemission process carried out in collaboration with Mona Berciu.