Study of the Mott Transition in the Three-Dimensional Hubbard Model |
| F. Mancini and V. Turkowski Dipartimento di Fisica "E.R. Caianiello" - Unita INFM di Salerno Universita degli Studi di Salerno, 84081 Baronissi (SA), Italy |
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| Received: April 6, 2001; in final form December 22, 2001 |
| The Mott-Hubbard transition in the three-dimensional Hubbard model is studied by means of the composite operator method. Analytical and numerical calculations show the existence of a critical value Uc of the Coulomb interaction which separates paramagnetic insulating and metallic phases. In the composite operator method the ratio Uc/W, where W is the band width, has the same value as in the two-dimensional case. The ground state of the Mott insulator is characterized by a local antiferromagnetic order where the electrons keep some mobility, but this latter must be compatible with the local ordering. By analyzing the intersite hopping it is possible to establish that some correlation functions behave as order parameters in the insulating phase. |
| DOI: 10.12693/APhysPolA.101.505 PACS numbers: 71.10.-w, 71.10.Fd, 71.30.+h |