Probing ultrafast non-equilibrium dynamics in an organic-dimer Mott insulator with terahertz-infrared continuum probe pulses

We apply optical-pump terahertz-infrared-probe reflection spectroscopy to study the non-equilibrium dynamics in the Mott insulator kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl (kappa-Cl), following intra-molecular electronic excitation of the organic dimers. The perturbation and subsequent relaxation of the correlated electronic system is treated with a global spectral analysis including a bleach of the inter-Hubbard-band transition and a photoinduced low-frequency contribution from the excitations above the Mott gap, providing a more complete picture of the nature of the excited states.