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Electron orderings in the (hard‐core) boson–fermion model
Author(s) -
Sidowski M.,
Robaszkiewicz S.
Publication year - 2007
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/pssb.200674630
Subject(s) - physics , charge density wave , charge (physics) , fermion , superconductivity , condensed matter physics , electron , coupling (piping) , singlet state , quantum electrodynamics , quantum mechanics , materials science , excited state , metallurgy
Abstract The system of coexisting local pairs and itinerant electrons described by the (hard‐core) boson–fermion model is analysed, taking into account both the intersubsystem charge exchange coupling I 0 as well as the density–density interaction V 0 . In our preliminary report [Acta Phys. Pol. A 109 , 647 (2006)] we have shown within an extended mean‐field approach that at T = 0 the model considered can exhibit not only the superconducting (SC) but also the charge density wave (CDW) phases as well as the so called charge Kondo state (CKS), which is characterised by a compensation of a local charge moment (isospin singlet). Here we shortly conclude those findings and present several new results concerning this subject. In particular the mutual stability of various phases, including the mixed ordered state (SC‐CKS) is analysed and the effects of the deviation from half‐filling on the properties of the system are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)