Reduced pairing hamiltonian for interatomic two-electron exchange in layered cuprates

TL;DR

This paper develops a detailed tight-binding model for layered cuprates, fitting experimental data and deriving a BCS kernel for interatomic electron exchange, advancing understanding of high-temperature superconductivity.

Contribution

It introduces a comprehensive LCAO tight-binding model for cuprates and derives a BCS kernel based on interatomic exchange, linking band structure to pairing mechanisms.

Findings

Fitted Fermi surface to ARPES data.

Derived a BCS kernel from interatomic exchange.

Provided a detailed model for high-Tc cuprates.

Abstract

A detailed Linear Combination of Atomic Orbitals (LCAO) tight-binding model is developed for the layered High-Temperature Superconductor cuprates. The band structure of these materials is described using a sigma-band Hamiltonian employing Cu4s, Cu3d_x^2-y^2, O2p_x and O2p_y atomic orbitals. The Fermi level and the shape of the resulting Fermi surface are fitted to recent Angle Resolved Photon Emission Spectroscopy (ARPES) data to realistically determine the dispersion in the conduction band. Electron-electron interactions and, ultimately, Cooper pairing is obtained by introducing a Heitler-London, two-electron exchange between adjacent orbitals within the CuO_2 plane. Finally, using the LCAO wavefunctions determined by the band structure fit, the Bardeen-Cooper-Schrieffer type kernel is derived for interatomic exchange.