Properties of the half-filled Hubbard model investigated by the strong coupling diagram technique

Abstract

The equation for the electron Green's function of the fermionic Hubbard model, derived using the strong coupling diagram technique, is solved self-consistently for the near-neighbor form of the kinetic energy and for half-filling. In this case the Mott transition occurs at the Hubbard repulsion $U_c\approx 6.96t$, where $t$ is the hopping constant. The calculated spectral functions, density of states and momentum distribution are compared with results of Monte Carlo simulations. A satisfactory agreement was found for $U>U_c$ and for temperatures, at which magnetic ordering and spin correlations are suppressed. For $U<U_c$ and lower temperatures the theory describes qualitatively correctly positions and widths of spectral continua, variations of spectral shapes and occupation numbers with changing wave vector and repulsion. The locations of spectral maxima turn out to be close to the positions of $\delta$-function peaks in the Hubbard-I approximation.

arXiv comment7 pages, 7 figures

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Cited by in corpus (5)

• Influence of spin and charge fluctuations on spectra of the two-dimensional Hubbard model
• The Hubbard model in the strong coupling theory at arbitrary filling
• Continuum of many-particle states near the metal-insulator transition in the Hubbard model
• The Hubbard model in strong magnetic field: Low-frequency quantum oscillations due to strong electron correlations
• Spin and charge fluctuations in the Hubbard model