Volume 50, Number 2, April II 2000
|Page(s)||229 - 235|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 September 2002|
The Mott-Hubbard transition and the paramagnetic insulating state in the two-dimensional Hubbard model
Dipartimento di Scienze Fisiche “E. R. Caianiello”, Unità INFM di
Università degli Studi di Salerno - 84081
Baronissi, Salerno, Italy
Corresponding author: email@example.com
Accepted: 27 January 2000
The Mott-Hubbard transition is studied in the context of the two-dimensional Hubbard model. Analytical calculations show the existence of a critical value Uc of the potential strength which separates a paramagnetic metallic phase from a paramagnetic insulating phase. Calculations of the density of states and double occupancy show that the ground state in the insulating phase contains always a small fraction of empty and doubly occupied sites. The structure of the ground state is studied by considering the probability amplitude of intersite hopping. The results indicate that the ground state of the Mott insulator is characterized by a local antiferromagnetic order; the electrons keep some mobility, but this mobility must be compatible with the local ordering. The vanishing of some intersite probability amplitudes at puts a constraint on the electron mobility. It is suggested that such quantities might be taken as the quantities which control the order in the insulating phase.
PACS: 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 71.27.+a – Strongly correlated electronic systems; heavy fermions / 71.30.+h – Metal-insulator transition and other electronic transitions
© EDP Sciences, 2000
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