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arXiv · 2207.03141

Exciton-assisted low-energy magnetic excitations in a photoexcited Mott insulator on a square lattice

Kenji Tsutsui·Kazuya Shinjo·Shigetoshi Sota·Takami Tohyama
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Abstract

The photoexcitation of a Mott insulator on a square lattice weakens the intensity of both single- and two-magnon excitations as observed in time-resolved resonant-inelastic X-ray scattering and time-resolved Raman scattering, respectively. However, the spectral changes in the low-energy regions below the magnons have not yet been clearly understood. To uncover the nature of the photoinduced low-energy magnetic excitations of the Mott insulator, we numerically investigate the transient magnetic dynamics in a photoexcited half-filled Hubbard model on a square lattice. After turning off a pump pulse tuned for an absorption edge, new magnetic signals clearly emerge well below the magnon energy in both single- and two-magnon excitations. We find that the low-energy excitations are predominantly created via excitonic states at the absorption edge. These exciton-assisted magnetic excitations may provide a possible explanation for the low-energy spectral weight in a recent time-resolved two-magnon Raman scattering experiment for insulating YBa$_2$Cu$_3$O$_{6.1}$.

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Kenji Tsutsui, Kazuya Shinjo, Shigetoshi Sota, Takami Tohyama. 2022-07-07. Exciton-assisted low-energy magnetic excitations in a photoexcited Mott insulator on a square lattice. https://doi.org/10.1038/s42005-023-01158-4

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