Electron spectrum and superconductivity in the t-J model at moderate doping.

Plakida N. M., Oudovenko V. S.

Max Planck Inst Phys Komplexer Syst Nothnitzerstr 38 D-01187 Dresden Germany
Joint Inst Nucl Res Dubna 141980 Russia
Max Planck Inst Festkorperforsch D-70569 Stuttgart Germany

A microscopical theory of electron spectrum and superconductivity within the two-dimensional t-J model in paramagnetic state is proposed. By employing the projection technique for the Green functions in terms of the Hubbard operators self-consistent Eliashberg equations are derived. A strong coupling of electrons with spin and charge fluctuations due to exchange and kinematical interactions is obtained. In the normal state, one-electron spectral functions reveal narrow quasiparticle peaks close to the Fermi surface (FS) with an additional broad incoherent band. The FS changes from holelike at low doping to electronlike for hole concentrations delta> 0.3. In the superconducting state we observe d-wave pairing with the maximal T(c)similar or equal to 0.04t at optimal doping delta=0.3. [S0163-1829(99)04513-0].

Physical Review B, 59 11949-11961, 1999.

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