Drude weight of the two-dimensional Hubbard model - Reexamination of finite-size effect in exact diagonalization study

Hiroki Nakano, Yoshinori Takahashi, Masatoshi Imada

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The Drude weight of the Hubbard model on the two-dimensional square lattice is studied by the exact diagonalizations applied to clusters up to 20 sites. We carefully examine finite-size effects by consideration of the appropriate shapes of clusters and the appropriate boundary condition beyond the limitation of employing only the simple periodic boundary condition. We successfully capture the behavior of the Drude weight that is proportional to the squared hole doping concentration. Our present result gives a consistent understanding of the transition between the Mott insulator and doped metals. We also find, in the frequency dependence of the optical conductivity, that the mid-gap incoherent part emerges more quickly than the coherent part and rather insensitive to the doping concentration in accordance with the scaling of the Drude weight.

Original languageEnglish
Article number034705
Journaljournal of the physical society of japan
Issue number3
Publication statusPublished - 2007 Mar 1



  • Drude weight
  • Hubbard model
  • Lanczos method
  • Metal-insulator transition
  • Optical conductivity

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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