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arXiv · 2205.05172

Keldysh space control of charge dynamics in a strongly driven Mott insulator

Xinwei Li·Honglie Ning·Omar Mehio·Hengdi Zhao·Min-Cheol Lee·Kyungwan Kim·Fumihiko Nakamura·Yoshiteru Maeno·Gang Cao·David Hsieh
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Abstract

The fate of a Mott insulator under strong low frequency optical driving conditions is a fundamental problem in quantum many-body dynamics. Using ultrafast broadband optical spectroscopy, we measured the transient electronic structure and charge dynamics of an off-resonantly pumped Mott insulator Ca$_2$RuO$_4$. We observe coherent bandwidth renormalization and nonlinear doublon-holon pair production occurring in rapid succession within a sub-100 femtosecond pump pulse duration. By sweeping the electric field amplitude, we demonstrate continuous bandwidth tuning and a Keldysh cross-over from a multi-photon absorption to quantum tunneling dominated pair production regime. Our results provide a procedure to control coherent and nonlinear heating processes in Mott insulators, facilitating the discovery of novel out-of-equilibrium phenomena in strongly correlated systems.

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Xinwei Li, Honglie Ning, Omar Mehio, Hengdi Zhao, Min-Cheol Lee, Kyungwan Kim, Fumihiko Nakamura, Yoshiteru Maeno, Gang Cao, David Hsieh. 2022-05-10. Keldysh space control of charge dynamics in a strongly driven Mott insulator. https://doi.org/10.1103/physrevlett.128.187402

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