Fig. 3: 2DCS of a correlated band insulator.
From: Multidimensional coherent spectroscopy of correlated lattice systems
a Sketch of the correlated dimer model. The solid bonds with hopping ti form dimers, while the dashed bonds with hopping to connect adjacent dimers. Excitations within the dimer (purple arrow) create a doublon/holon state on the dimer. b Charge excitations between dimers (green arrow) create triply occupied and singly occupied dimers, with additional electrons or holons in the antibonding or bonding states. c Interacting density of states of the Mott insulating single band Hubbard model (red) and the dimerized correlated band insulator (blue). e 2DCS signal from the intradimer (e1) and interdimer (e2) current for the correlated dimer model. We use different color ranges since the intensity of the intradimer signal is larger than that of the interdimer signal. d, f Keldysh diagrams for the indicated features in the interdimer 2DCS signal.the charge gap is a correlated hybridization.
