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Mott Transition in the Two‐Dimensional Hubbard Model
Author(s) -
PérezNavarro A.,
CostaQuintana J.,
LópezAguilar F.
Publication year - 2000
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(200002)217:2<869::aid-pssb869>3.0.co;2-m
Subject(s) - hubbard model , physics , antiferromagnetism , ground state , perturbation theory (quantum mechanics) , spin density wave , mott transition , quantum mechanics , condensed matter physics , wave vector , quantum electrodynamics , superconductivity
We are interested in the description of the Mott‐Hubbard transition from a perturbation theory arising from a two‐dimensional Hubbard model. We calculate the self‐energy within the random phase approximation and a double‐Lorentzian as a non‐interacting density of states. The paramagnetic ground state is unstable for realistic values of U , since the self‐energy presents some inconsistencies; one of them is that its imaginary part presents more than one zero, which is a violation of the Luttinger theorem. We use a Bogolyubov transformation and within a spin density wave mean field, the antiferromagnetic correlations of wave vector Q = ( π / a , π / a ) are included. We recalculate the self‐energy in the new ground state and then it is able to describe the Mott‐Hubbard transition, and the Luttinger theorem is satisfied.