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Doping induced metal-insulator transition in two-dimensional Hubbard, $t-U$, and extended Hubbard, $t-U-W$, models

F. F. Assaad·M. Imada
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Abstract

We show numerically that the nature of the doping induced metal-insulator transition in the two-dimensional Hubbard model is radically altered by the inclusion of a term, $W$, which depends upon a square of a single-particle nearest-neighbor hopping. This result is reached by computing the localization length, $ξ_l$, in the insulating state. At finite values of $W$ we find results consistent with $ξ_l \sim | μ- μ_c|^{- 1/2} $ where $μ_c$ is the critical chemical potential. In contrast, $ξ_l \sim | μ- μ_c|^{-1/4}$ for the Hubbard model. At finite values of $W$, the presented numerical results imply that doping the antiferromagnetic Mott insulator leads to a $d_{x^2 - y ^2}$ superconductor.

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F. F. Assaad, M. Imada. 1997-11-18. Doping induced metal-insulator transition in two-dimensional Hubbard, $t-U$, and extended Hubbard, $t-U-W$, models. https://doi.org/10.1103/physrevb.58.1845

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