Description of High-Temperature Superconducting State in BSLCO Compound

Szczȩśniak, R.; Durajski, A. P.

doi:10.1007/s10948-014-2836-1

Cited by 7 publications

(7 citation statements)

References 29 publications

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“…In particular, it was shown that the model allows to calculate correctly the critical temperature and the energy gap at zero Kelvin. It should be noted that the appropriate calculations were carried out for the large number of the chemical compounds, and each time obtained results were consistent with the experimental data .…”

Section: The Eliashberg Approach the Pseudogap And The Pairing Mechsupporting

confidence: 62%

Pseudogap in the Eliashberg approach based on electron‐phonon and electron‐electron‐phonon interaction

2017

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The properties of the superconducting and the anomalous normal state were described by using the Eliashberg method. The pairing mechanism was reproduced with the help of the Hamiltonian, which models the electron-phonon and the electron-electron-phonon interaction (EEPh). The set of the Eliashberg equations, which determines the order parameter function (ϕ), the wave function renormalization factor (Z), and the energy shift function (χ ), was derived. It was proven that for the sufficiently large values of the EEPh potential, the doping dependence of the order parameter (ϕ/Z) has the analogous course to that observed experimentally in cuprates. The energy gap in the electron density of states is induced by Z and χ -the contribution from ϕ is negligible. The electron density of states possesses the characteristic asymmetric form and the pseudogap is observed above the critical temperature.

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Section: The Eliashberg Approach the Pseudogap And The Pairing Mechsupporting

confidence: 62%

Pseudogap in the Eliashberg approach based on electron‐phonon and electron‐electron‐phonon interaction

2017

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“…For example, there are great difficulties in explaining the energy gap dependence on the temperature for the lower values of δ [39,[47][48][49][50]. The issue, which is not settled, is also the origin of the pseudogap.…”

Section: Introductionmentioning

confidence: 99%

Non-BCS Temperature Dependence of Energy Gap in Thin Film Electron-Doped Cuprates

Szczȩśniak

Durajski

2016

J Supercond Nov Magn

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We investigate the dependence of the energy gap (G) on the temperature (T ) for the electron-doped hightemperature superconductors. The following compounds, in the form of the thin films, have been taken into consideration: La 2−x Ce x CuO 4 (LCCO), Pr 2−x Ce x CuO 4 (PCCO), and Nd 2−x Ce x CuO 4 (NCCO). It was found that G(T ) deviates from the BCS prediction more, if a concentration of cerium assumes the lower values. For the lowest concentration (in the case of LCCO and NCCO), the function G (T ) is not quite like the BCS curve, which is connected with the existence of the residual Nernst region. Next, it has been pointed out that the NCCO superconductor becomes structurally unstable for the maximum concentration of cerium, which is leading to the anomalous dependence of the energy gap on the temperature and the induction of the wide Nernst region.

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“…24 Another important contribution was given by Szczȩśniak et al in Refs. [25][26][27][28][29]. They used the ideas used by Hirsch et al [5][6][7][8][9] in order to derive an effective one-band Hamiltonian with a four-fermion potential.…”

Section: Introductionmentioning

confidence: 99%

The generalized Lang–Firsov transformation and the three- and the four-fermion interactions in a lattice fermion model

Tarasewicz

2016

Int. J. Mod. Phys. B

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A new two-band polaronic Hamiltonian is derived from a generalized periodic Anderson model. This is achieved by making use of a new generalized Lang-Firsov transformation on the periodic Anderson model completed with new terms representing the interactions between local phonons and both single electrons and pairs of them with opposite spins residing on the same lattice site. The novelty consists in the appearance of three-and four-fermion terms in the resulting Hamiltonian. The interaction between phonons and pairs of electrons with opposite spins was introduced at first time by Hirsch in order to describe the weakening of the Coulomb repulsion acting between two electrons with opposite spins occupying the same atomic orbital observed in experiments. The threefermion terms represent the local interactions between a single polarons from one band and a pair of them with opposite spins from the other one. Whether it is attractive or repulsive depends on the signs of couplings of phonons to electron pairs. The fourfermion term stands for the local attraction between pairs of electrons with opposite spins from two bands. In the case of presence of such an interaction, the formation of local fermion quartets is possible. A simplified version of the generalized Hamiltonian is investigated in the end of the paper. The influence of the three-and the four-fermion terms on the properties of the two-band fermion system with two order parameters is examined. Expressions for the order parameters at zero temperatures and finite ones along with the critical temperatures for two-electron subsystems have been derived. This was achieved in the atomic limit by making use of the mean field method.

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Description of High-Temperature Superconducting State in BSLCO Compound

Cited by 7 publications

References 29 publications

Pseudogap in the Eliashberg approach based on electron‐phonon and electron‐electron‐phonon interaction

Pseudogap in the Eliashberg approach based on electron‐phonon and electron‐electron‐phonon interaction

Non-BCS Temperature Dependence of Energy Gap in Thin Film Electron-Doped Cuprates

The generalized Lang–Firsov transformation and the three- and the four-fermion interactions in a lattice fermion model

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