On properly integrating the electronic Raman and optical infra-red spectra of HTSC cuprate materials

TL;DR

This paper interprets electronic Raman and IR spectra of high-temperature cuprate superconductors using a negative-U boson-fermion crossover model, highlighting the importance of doping and quasiparticle coherence.

Contribution

It introduces a comprehensive interpretation framework for spectroscopic data of HTSC cuprates based on the negative-U model, connecting spectral features with doping and quasiparticle coherence.

Findings

Spectroscopic features follow the condensate gap and local-pair binding energy.

Doping level p_c = 0.185 is critical for quasiparticle coherence.

Magnetic field IR results provide key insights.

Abstract

New electronic Raman and I.R. spectroscopy results from optimally and overdoped high temperature superconducting (HTSC) cuprate systems are interpreted in terms of the negative-U, boson-fermion crossover model. Distinction is made between those features which follow the condensate gap, 2Delta(p), and those that are set by the local-pair binding energy, cursive U(p). The critical role of doping level psubc = 0.185 is highlighted in conjunction with the matter of developing quasiparticle incoherence, making connection here with recent transport and related results. E//c IR results in magnetic fields parallel and perpendicular to c prove particularly illuminating. The general scheme developed continues to embrace all experimental data very satisfactorily.