Low Temperature Physics: 42, 1041 (2016); https://doi.org/10.1063/1.4969907
Физика Низких Температур: Том 42, Выпуск 11 (Ноябрь 2016), c. 1328-1344    ( к оглавлению , назад )

Electron dynamics in the normal state of cuprates: Spectral function, Fermi surface and ARPES data

E.E. Zubov

G.V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Boulevard, Kyiv 03680, Ukraine

Donetsk National University, 21 Str. 600-richchia, Vinnytsia 21021, Ukraine
E-mail: eezubov@ukr.net

Received March 28, 2016

Аннотация

An influence of the electron–phonon interaction on excitation spectrum and damping in a narrow band electron subsystem of cuprates has been investigated. Within the framework of the t–J model an approach to solving a problem of account of both strong electron correlations and local electron–phonon binding with characteristic Einstein mode ω0 in the normal state has been presented. In approximation Hubbard-I it was found an exact solution for the polaron bands. We established that in the low-dimensional system with a pure kinematic part of Hamiltonian a complicated excitation spectrum is realized. It is determined mainly by peculiarities of the lattice Green’s function. In the definite area of the electron concentration and hopping integrals a correlation gap may be possible on the Fermi level. Also, in specific cases it is observed a doping evolution of the Fermi surface. We found that the strong electron–phonon binding enforces a degree of coherence of electron–polaron excitations near the Fermi level and spectrum along the nodal direction depends on wave vector module weakly. It corresponds to ARPES data. A possible origin of the experimentally observed kink in the nodal direction of cuprates is explained by fine structure of the polaron band to be formed near the mode –ω0.

PACS: 79.60.–i Photoemission and photoelectron spectra;
PACS: 74.72.–h Cuprate superconductors;
PACS: 71.27.+a Strongly correlated electron systems; heavy fermions;
PACS: 71.38.–k Polarons and electron–phonon interactions.

Ключевые слова: electron–phonon interaction, t–J model, polaron, cuprates, ARPES, Fermi surface, chemical potential, spectral density.

Published online: September 26, 2016