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arXiv · 2012.15652

Nonequilibrium optical response of a one-dimensional Mott insulator

Julian Rincon·Adrian E. Feiguin
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Abstract

We define, compute and analyze the nonequilibrium differential optical conductivity of the one-dimensional extended Hubbard model at half-filling after applying a pump pulse, using the time-dependent density matrix renormalization group method. The melting of the Mott insulator is accompanied by a suppression of the local magnetic moment and ensuing photogeneration of doublon-holon pairs. The differential optical conductivity reveals $(i)$ mid-gap states related to parity-forbidden optical states, and $(ii)$ strong renormalization and hybridization of the excitonic resonance and the absorption band, yielding a Fano resonance. We offer evidence and interpret such a resonance as a signature of nonequilibrium optical excitations resembling excitonic strings, (bi)excitons, and unbound doublon-holon pairs, depending on the magnitude of the intersite Coulomb repulsion. We discuss our results in the context of pump and probe spectroscopy experiments on organic Mott insulators.

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Julian Rincon, Adrian E. Feiguin. 2020-12-31. Nonequilibrium optical response of a one-dimensional Mott insulator. https://doi.org/10.1103/physrevb.104.085122

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