Journal article

Normal state bottleneck and nematic fluctuations from femtosecond quasiparticle relaxation dynamics in Sm(Fe,Co)AsO

We investigate temperature and fluence dependent dynamics of the photoexcited quasiparticle relaxation and low-energy electronic structure in electron-doped 1111-structure Sm(Fe0.93Co0.07)AsO single crystal. We find that the behavior is qualitatively identical to the 122-structure Ba(Fe,Co)(2)As-2 including the presence of a normal state pseudogap and a marked twofold symmetry breaking in the tetragonal phase that we relate to the electronic nematicity. The twofold symmetry breaking appears to be a general feature of the electron-doped iron pnictides.


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