Strong coupling diagram technique for the three-band Hubbard model

A. Sherman
2016 International Journal of Modern Physics B  
Using the strong coupling diagram technique equations are derived for hole Green's functions of the three-band Hubbard model, which describes Cu-O planes of high-T_c cuprates. The equations are self-consistently solved in the approximation, in which the series for the irreducible part in powers of the oxygen-copper hopping constant is truncated to two lowest-order terms. For parameters used for hole-doped cuprates the calculated energy spectrum consists of lower and upper Hubbard subbands of
more » ... dominantly copper nature, oxygen bands with a small admixture of copper states and the Zhang-Rice states of mixed nature, which are located between the lower Hubbard subband and oxygen bands. The spectrum contains also pseudogaps near transition frequencies of Hubbard atoms on copper sites.
doi:10.1142/s0217979216420042 fatcat:s57td6mayrgvvomn7ekqm2uy44