Continuum of many-particle states near the metal-insulator transition in the Hubbard model

Abstract

The strong coupling diagram technique is used for investigating states near the metal-insulator transition in the half-filled two-dimensional repulsive Hubbard model. The nonlocal third-order term is included in the irreducible part along with local terms of lower orders. Derived equations for the electron Green's function are solved by iteration for moderate Hubbard repulsions and temperatures. Starting iteration from Green's functions of the Hubbard-I approximation with various distances of poles from the real frequency axis continua of different metallic and insulating solutions are obtained. The insulating solutions vary in the width of the Mott gap, while the metallic solutions differ in the shape of the spectral function in the vicinity of the Fermi level. Besides, different scenarios of the metal-insulator transition -- with a sudden onset of a band of mobile states near the Fermi level and with gradual closure of the Mott gap -- are observed with a change in temperature. In spite of these dissimilarities, all solutions have a common curve separating metallic and insulating states in the phase diagram. Near this curve metallic and insulating solutions coexist. For moderate Hubbard repulsions metallic solutions are not Fermi liquids.

10 pages, 9 figures

References in corpus (9)

• Cluster Dynamical Mean Field Theory of the Mott Transition
• Variational cluster approach to spontaneous symmetry breaking: The itinerant antiferromagnet in two dimensions
• Local Order and the gapped phase of the Hubbard model: a plaquette dynamical mean field investigation
• First order Mott transition at zero temperature in two dimensions: Variational plaquette study
• A comparison between methods of analytical continuation for bosonic functions
• Fluctuating charge density waves in the Hubbard model
• Magnetic susceptibility of the two-dimensional Hubbard model using a power series for the hopping constant
• Quasiparticle states of the Hubbard model near the Fermi level
• Properties of the half-filled Hubbard model investigated by the strong coupling diagram technique

Cited by in corpus (6)

• Influence of spin and charge fluctuations on spectra of the two-dimensional Hubbard model
• The $t$-$t^{\prime }$-$t^{\prime \prime }$-$U$ Hubbard model and Fermi-level peak
• Magnetic properties and temperature variation of spectra in the Hubbard model
• Spin and charge fluctuations in the two-band Hubbard model
• Effective interaction in a non-Fermi liquid conductor and spin correlations in under-doped cuprates
• Manifestations of spin and charge fluctuations in spectra of the Hubbard model