Manifestation of the Upper Hubbard band in the 2D Hubbard model at low electron density

Низкоразмерные структуры


  • M.Yu. Kagan P.L. Kapitza Institute for Physical Problem, 2 ul. Kosygina, Moscow 119334, Russia
  • V.V. Val’kov Kirensky Institute of Physics, Akademgorodok, 50, bld. 38, Krasnoyarsk 660036, Russia
  • P. Woelfle Institute for Theoretical Condensed Matter physics, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str., 1, Karlsruhe D-76131, Germany


Ключові слова:

Hubbard model, Green-function, low electron density.


We consider the 2D Hubbard model in the strong-coupling case (U >> W) and at low electron density (nd 2 << 1). We find an antibound state as a pole in the two-particle T-matrix. The contribution of this pole in the self-energy reproduces a two-pole structure in the dressed one-particle Green-function similar to the Hubbard-I approximation. We also discuss briefly the Engelbrecht-Randeria mode which corresponds to the pairing of two holes below the bottom of the band for U >> W and low electron density. Both poles produce nontrivial corrections to Landau Fermi-liquid picture already at low electron density but do not destroy it in 2D.


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Як цитувати

Kagan, M.; Val&#8217;kov, V.; Woelfle, P. Manifestation of the Upper Hubbard Band in the 2D Hubbard Model at Low Electron Density: Низкоразмерные структуры. Fiz. Nizk. Temp. 2011, 37, 1046-1052.