Doublon bottleneck in the ultrafast relaxation dynamics of hot electrons in 1 T -TaS 2

The authors use a combination of femtosecond photoelectron emission spectroscopy and Boltzmann equation calculations to show the formation of doublons - occupation of states with two electrons in strongly correlated materials - and how these can determine a bottleneck in the relaxation of excited electrons in delocalized, Bloch-like states.