Electron-Phonon Interaction in the High- Cuprates in the Framework of the Van Hove Scenario

Abstract

Electron-lattice interaction was the original idea of Müller and Berdnorz who chose copper oxides, because of the strong Jahn-Teller effect of the Cu ion leading to the formation of bipolarons. Later several experimental features led to theoretical models based on strong electronic correlations. The high- superconductors cuprates are quasi-bidimensional (2D) and thus lead to the existence of Van Hove singularities (VHs) in the band structure, that is, a peak in the electronic density of states. The presence of VHs near the Fermi-level in the cuprates is now well established. In this context we show that many physical properties of these materials can be explained using electron-phonon interaction, in particular the high critical temperature , the anomalous isotope effect, the superconducting gap and its anisotropy, and the marginal Fermi-liquid properties. These compounds present a topological transition for a critical hole doping hole per plane.

Superconductivity and the Van Hove Scenario

“…18, decrease with the doping from the optimum dop- ing to the overdoped region in these calculations. We obtain also an interesting result, which is the decrease of the anisotropy ratio α with doping [22,23,52]. This is confirmed by ARPES results.…”

“…8 for the constant energy surfaces (CES) in k-space [22,23]. This is very well confirmed by the results of Ino [24] using angular resolved photoemission spectroscopy (ARPES) (see Fig.…”

Comprehensive phase diagram of two-dimensional space charge doped Bi2Sr2CaCu2O8+x

“…This is confirmed in Fig. 4b where an exponential dependence is found between the two quantities 16, 19 and in Fig. 4c where the horizontal 1/ qR H axis is plotted in logarithmic scale yielding a result very similar to the phase diagram obtained in Fig.…”

Signature of electron-phonon interaction in high temperature superconductors

“…in high temperature superconductivity (HTSC). [2][3][4][5][6][7][8][9][10][11][12][13] In the work available so far it emerges that the electron-phonon interactions are directly or indirectly involved either via diagonal or off-diagonal interactions 14 or Van Hove scenario 15 or rattling phonon modes 16,17 in the mechanism of superconductivity. In the recent work 18 the superconductivity has been described in the framework of phonon mediated BCS theory in the case of iso-structural Ba 24 Ge 100 and Ba 24 Si 100 and one can equally well believe that Cooper pairs occur because of electron-phonon interaction.…”