1997/11/18 by Fakher F. Assaad, F. F. Assaad, Masatoshi Imada +1 · 3 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.58.1845
19 pages (latex) including 7 figures in encapsulated postscript format. Submitted for publication in Phys. Rev. B
arxiv created 1997/11/18 · openalex publication_date 1998/07/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We show numerically that the nature of the doping-induced metal-insulator transition in the two-dimensional Hubbard model with hopping matrix element t and Coulomb repulsion U is radically altered by the inclusion of a term W that depends upon a square of a single-particle nearest-neighbor hopping. This result is reached by computing the localization length \ensuremathξl in the insulating state. At W/t=0.05 and U/t=4, we find results consistent with \ensuremathξl\ensuremath∼|\ensuremathμ\ensuremath-\ensuremathμc|^\ensuremath-1/2 where \ensuremathμc is the critical chemical potential. In contrast, \ensuremathξl\ensuremath∼|\ensuremathμ\ensuremath-\ensuremathμc|^\ensuremath-1/4 for the Hubbard model at U/t=4. At half-filling, we calculate the density of states N(\ensuremathω). The large value of N(\ensuremathω) in the vicinity of \ensuremathω=\ensuremathμc present at W=0 is suppressed with growing values of W. At finite doping, the d-wave pair-field correlations are enhanced with growing values of W. The numerical results imply that at finite values of W doping the antiferromagnetic Mott insulator leads to a d_x2\ensuremath-y2 superconductor.