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Charge and spin excitation spectra in the one-dimensional Hubbard model with next-nearest-neighbor hopping

S. Nishimoto·T. Shirakawa·Y. Ohta
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Abstract

The dynamical density-matrix renormalization group technique is used to calculate spin and charge excitation spectra in the one-dimensional (1D) Hubbard model at quarter filling with nearest-neighbor $t$ and next-nearest-neighbor $t'$ hopping integrals. We consider a case where $t$ ($>0$) is much smaller than $t'$ ($>0$). We find that the spin and charge excitation spectra come from the two nearly independent $t'$-chains and are basically the same as those of the 1D Hubbard (and t-J) chain at quarter filling. However, we find that the hopping integral $t$ plays a crucial role in the short-range spin and charge correlations; i.e., the ferromagnetic spin correlations between electrons on the neighboring sites is enhanced and simultaneously the spin-triplet pairing correlations is induced, of which the consequences are clearly seen in the calculated spin and charge excitation spectra at low energies.

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S. Nishimoto, T. Shirakawa, Y. Ohta. 2007-01-24. Charge and spin excitation spectra in the one-dimensional Hubbard model with next-nearest-neighbor hopping. https://doi.org/10.1103/physrevb.77.115102

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