Ultrafast dynamics of excitons in delafossite CuScO thin films

摘要

Ultrafast carrier dynamics were investigated in a delafossite CuScO2, a material with a remarkablynlarge binding energy of exciton u0002u00040.4 eVu0003, using femtosecond transient transmission spectroscopy.nDifferential transmission spectra showed dispersive structures in the excitonic resonance energies.nWe have observed a delayed rise-up on a time scale of 10 ps, suggesting slow carrier cooling. It isnfollowed by a slower decay, time constant of which corresponds to the lifetime of excitonnu0002approximately 0.75 nsu0003. These results were analyzed in terms of the generalized many-body Elliottnmodel, accounting for a screening effect of excitons. © 2010 American Institute of Physics.nu0005doi:10.1063/1.3436548