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Energy spectrum of extended Hubbard model with spin‐dependent hopping and related spin ladder model
Author(s) -
Cheranovskii V. O.,
Ezerskaya E. V.,
Özkan I.
Publication year - 2002
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.10177
Subject(s) - hubbard model , physics , magnon , spins , density matrix renormalization group , spin (aerodynamics) , condensed matter physics , bound state , ising model , spectrum (functional analysis) , renormalization group , ground state , excitation , quantum mechanics , superconductivity , ferromagnetism , thermodynamics
We studied the energy spectrum of the 1‐D extended Hubbard model with spin‐dependent hopping and related spin ladder system formed by two coupled XXZ spin 1/2 chains with the interchain interaction of Ising type. It was proved that the model excitation spectrum has no gap excepting some special values of z ‐projection of the ground‐state total spin. The thorough analytic consideration of two‐magnon states was given. The existence up to five bound states at specified value of quasimomentum of the pair of inverted spins was shown. We also present the results of density matrix renormalization group calculations that showed nonadequacy of the pair approximation for n ‐magnon bound states of the extended model with the strong electron–electron interactions. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002