Premium
Broken symmetry solutions of the extended Hubbard model
Author(s) -
Ozaki MasaAki
Publication year - 1992
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560420107
Subject(s) - hubbard model , antiferromagnetism , physics , charge (physics) , condensed matter physics , symmetry (geometry) , wave vector , charge ordering , spin (aerodynamics) , symmetry breaking , order (exchange) , quantum mechanics , superconductivity , mathematics , thermodynamics , geometry , finance , economics
This paper describes a group theoretical classification of the unrestricted Hartree–Fock ( UHF ) solution of the extended Hubbard model including nearest‐neighbor repulsion and exchange interactions. We derived systematically all types of the broken symmetry solution with a single‐order parameter for the ordering vector Q = (π,π). It is shown that there are four nonmagnetic states: a charge density wave (CDW), a charge current wave (CCW), and two bond‐order waves (BOW), and five magnetic states: an ordinary antiferromagnetic state (AF), a spin current wave (SCW), two axial spin bond‐order waves (ASBOW), and an helical spin bond‐order wave (HSBOW). We showed that these phases can be derived naturally from the irreducible decomposition of the Fourier transformed interaction and the self‐consistent field ( SCF ) condition. Some numerical results are given for the half‐filled case.