Janez Bonča with Andrea Damascelli and Mona Berciu from University of British Columbia in Vancouver used numerical simulations to study how electron pairs behave in strongly interacting quantum materials. In particular, they investigated how two electrons can be emitted together in a two-electron photoemission (2eARPES) experiment. Research has recently been published in Physical Review Letters. 

Authors showed that electrons coming from the same bound pair produced a characteristic signal that differed from the much larger background created by electrons emitted from different pairs. This signal appeared at different energies and had a distinctive momentum pattern related to the symmetry of the pairs.

The authors demonstrated that these features are very general and should occur in many systems where electrons form pairs through interactions with other excitations in the material. Detecting these signatures experimentally would therefore provide direct evidence for electron pairing. In addition, the momentum pattern could distinguish between coherent superconducting pairs and incoherent “preformed” pairs. They also argued that these conclusions should remain valid at finite temperatures, finite electron densities, and in higher-dimensional systems.

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