High T{sub c} in cuprates as a universal property of the electron–phonon system

Journal Article · Sat Aug 15 00:00:00 EDT 2015 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776115080117· OSTI ID:22472132

Kagan, Yu. ^[1]

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1. National Research Centre Kurchatov Institute (Russian Federation)

The Eliashberg theory, which is generalized due to peculiar properties of the finite-width electron band for electron–phonon (EP) systems with a variable electron density of states (DOS), as well as with allowance for the electron–hole nonequivalence of the frequency behavior of the chemical potential renormalization depending on the doping level and electron correlations in the vertex function, is used to study T{sub c} in cuprates. The phonon contribution to the nodal anomalous electron Green’s function (GF) is considered. Pairing within the total width of the electron band, and not only in a narrow layer at the Fermi surface, is taken into account. The calculated frequency and temperature dependences, as well as the dependence on the doping level of the complex renormalization ReZ, ImZ of the mass, complex renormalization Reχ(ω), Imχ(ω) of the chemical potential, and DOS N(ε) renormalized due to the EP interaction are used to calculate the electron nodal anomalous GF. It is found that the effect of suppressing the high-frequency contribution to the Eliashberg equations derived anew for the EP system with a finite width of the electron band is a decisive factor for the manifestation of the effect of high-temperature superconductivity (HTSC). It is shown that in the vicinity of the optimal hole-type doping level in cuprates, the high value of T{sub c} is reproduced by the spectral function of the electron–phonon interaction, which is obtained from tunneling experiments. Upon an increase in the doping level, leading to an increase in the degree of electron–hole nonequivalence, the new logarithmic term appearing in the equations for T{sub c} has a tendency to increase T{sub c}, while intensification of damping of charge carriers (especially suppression of the cutoff factor) leads to a decrease in T{sub c}.

• OSTI ID: 22472132
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 121, Issue 2; Other Information: Copyright (c) 2015 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHARGE CARRIERS
CUPRATES
ELECTRON CORRELATION
ELECTRON DENSITY
ELECTRONS
FERMI LEVEL
GORKOV-ELIASHBERG THEORY
GREEN FUNCTION
HIGH-TC SUPERCONDUCTORS
HOLES
LAYERS
PHONONS
RENORMALIZATION
SPECTRAL FUNCTIONS
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
TUNNEL EFFECT
VERTEX FUNCTIONS