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arXiv · 1709.01297

Photoinduced absorptions inside the Mott gap in the two-dimensional extended Hubbard model

Kazuya Shinjo·Takami Tohyama
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Abstract

We theoretically investigate pump-probe optical responses in the two-dimensional extended Hubbard model describing cuprates by using a time-dependent Lanczos method. At half filling, pumping generates photoinduced absorptions inside the Mott gap. A part of low-energy absorptions is attributed to the independent propagation of photoinduced holons and doublons. The spectral weight just below the Mott gap increases with decreasing the on-site Coulomb interaction $U$. We find that the next-nearest-neighbor Coulomb interaction $V_1$ enhances this $U$ dependence, indicating the presence of biexcitonic contributions formed by two holon-doublon pairs. Photo-pumping in hole-doped systems also induces spectral weights below remnant Mott-gap excitations, being consistent with recent experiments. The induced weights are less sensitive to $V_1$ and may be related to the formation of a biexcitonic state in the presence of hole carriers.

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Kazuya Shinjo, Takami Tohyama. 2017-11-22. Photoinduced absorptions inside the Mott gap in the two-dimensional extended Hubbard model. https://doi.org/10.1103/physrevb.96.195141

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