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Phase diagram of the $t-t'-U$ chain at half filling

M. E. Torio·A. A. Aligia·H. A. Ceccatto
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Abstract

We study the half filled Hubbard chain including next-nearest-neighbor hopping $t'$. The model has three phases: one insulating phase with dominant spin-density-wave correlations at large distances (SDWI), another phase with dominant spin-dimer correlations or dimerized insulator (DI), and a third one in which long distance correlations indicate singlet superconductivity (SS). The boundaries of the SDWI are accurately determined numerically through a crossing of excited energy levels equivalent to the jump in the spin Berry phase. The DI-SS boundary is studied using several indicators like correlation exponent $K_ρ$, Drude weight $D_{c}$, localization parameter $z_{L}$ and charge gap $Δ_{c}$.

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M. E. Torio, A. A. Aligia, H. A. Ceccatto. 2003-02-05. Phase diagram of the $t-t'-U$ chain at half filling. https://doi.org/10.1103/physrevb.67.165102

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