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arXiv · 1908.09335

A charge model as an effective model of one-dimensional Hubbard and extended Hubbard systems: its application to linear optical spectrum calculations in large systems based upon many-body Wannier functions

Shu Ohmura·Akira Takahashi·Kaoru Iwano·Tokitake Yamaguchi·Kazuya Shinjo·Takami Tohyama·Shigetoshi Sota·Hiroshi Okamoto
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Abstract

We propose an effective model called the "charge model", for the half-filled one-dimensional Hubbard and extended Hubbard models. In this model, spin-charge separation, which has been justified from an infinite on-site repulsion ($U$) in the strict sense, is compatible with charge fluctuations. Our analyses based on the many-body Wannier functions succeeded in determining the optical conductivity spectra in large systems. The obtained spectra reproduce the spectra for the original models well even in the intermediate $U$ region of $U=5-10T$, with $T$ being the nearest-neighbor electron hopping energy. These results indicate that the spin-charge separation works fairly well in this intermediate $U$ region against the usual expectation and that the charge model is an effective model that applies to actual quasi-one-dimensional materials classified as strongly correlated electron systems.

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Shu Ohmura, Akira Takahashi, Kaoru Iwano, Tokitake Yamaguchi, Kazuya Shinjo, Takami Tohyama, Shigetoshi Sota, Hiroshi Okamoto. 2019-08-25. A charge model as an effective model of one-dimensional Hubbard and extended Hubbard systems: its application to linear optical spectrum calculations in large systems based upon many-body Wannier functions. https://doi.org/10.1103/physrevb.100.235134

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