Abstract
Microscopic theory of a high Tc cuprate Bi2Sr2CaCu2O8+x based on main pairing channel of electrons in CuO planes due to 40mev lateral vibrations of the apical oxygen atoms in adjacent the SrO ionic insulator layer is proposed. The separation between the vibrating charged atoms and the 2D electron gas creates the forward scattering peak leading in turn to the d-wave pairing within Eliashberg formalism. The phonon mode naturally explain the kink in dispersion relation observed by ARPES and the and effect of the O16 → O18 isotope substitution in the normal state. To describe the pseudogap physics a single band fourfold symmetric t-tʹ Hubbard model, with the hopping parameters tʹ ~-0.17t and the on site repulsion e U ∼ 6t. It described the Mott insulator at low doping, while at higher dopping the pseudogap physics (still strongly correlated) can be be approximated by the symmetrized mean field model and with renormalized U incorporating screening. The location of the transition line T*between the locally antiferromagnetic pseudogap and the paramagnetic overdoped phases and susceptibility (describing spin fluctuations coupling to 2DEG) are also obtained within this approximation. The superconducting d-wave gap mainly due to the phonon channel but is assisted by the spin fluctuations (15%–20%). The dependence of the gap and Tc on doping and effect of the isotope substitution are obtained and is consistent with experiments.
Original language | English |
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Article number | 055013 |
Journal | Journal of Physics Communications |
Volume | 5 |
Issue number | 5 |
DOIs | |
State | Published - 19 May 2021 |
Bibliographical note
Publisher Copyright:© 2021 The Author(s). Published by IOP Publishing Ltd.
Funding
We are grateful Prof. D Li, H C Kao, T X Ma, L L Wang, Y Guo, J Y Lin and Y Yeshurun for helpful discussions. Work of B R was supported by NSC of R O C Grants No. 101-2112-M-009-014-MY3.
Funders | Funder number |
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NSC of R O C | 101-2112-M-009-014-MY3 |
Keywords
- Electron phonon pairing
- High temperature superconductivity
- Hubbard model
- Pseudogap