Splitting of the lower subband of Hubbard fermions in the Shubin–Vonsowsky model under the influence of strong intersite correlations

The diagram technique for Hubbard operators is used to investigate the influence of intersite Coulomb interactions on the energy structure and Cooper instability of strongly correlated fermions. Allowance for intersite correlations in doped Mott-Hubbard insulators is shown to lead to a splitting of...

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Bibliographic Details
Published inJournal of experimental and theoretical physics Vol. 112; no. 1; pp. 108 - 120
Main Authors Val’kov, V. V., Korovushkin, M. M.
Format Journal Article
LanguageEnglish
Published Moscow Nauka/Interperiodica 01.01.2011
Springer
Subjects
Classical and Quantum Gravitation
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
COOPER PAIRS
CORRELATIONS
COULOMB FIELD
Disorder
DOPED MATERIALS
ELECTRONS
Elementary Particles
FEYNMAN DIAGRAM
FLUCTUATIONS
HUBBARD MODEL
KINETIC ENERGY
Order
Particle and Nuclear Physics
Phase Transition in Condensed System
Physics
Physics and Astronomy
Quantum Field Theory
Relativity Theory
RENORMALIZATION
SCATTERING AMPLITUDES
Solid State Physics
SUPERCONDUCTIVITY
Superconductors
TRANSITION TEMPERATURE
Strength Operator
Matsubara Frequency
Mass Operator
Spectral Intensity
Occupation Number
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Summary:The diagram technique for Hubbard operators is used to investigate the influence of intersite Coulomb interactions on the energy structure and Cooper instability of strongly correlated fermions. Allowance for intersite correlations in doped Mott-Hubbard insulators is shown to lead to a splitting of the lower subband of Hubbard fermions and to the formation of a band of fluctuation states as soon as the intersite interaction energy becomes comparable to or exceeds the mean kinetic energy. The spectral intensity of the splitoff band is proportional to the root-mean-square fluctuation of the occupation numbers and increases with doping level. The predicted effect changes significantly the structure of the density of electronic states. This leads to a renormalization of the pole of the scattering amplitude in the Cooper channel and manifests itself as a nonuniform (in electron concentration) modification of the dependence of the critical superconducting transition temperature.
ISSN:1063-7761
1090-6509
DOI:10.1134/S1063776110061056