Electron-phonon coupling in the undoped cuprate YBa2Cu3O6 estimated from Raman and optical conductivity spectra

D. Farina; G. De Filippis; A. S. Mishchenko; N. Nagaosa; Jhih-An Yang; D. Reznik; Th. Wolf; V. Cataudella

doi:10.1103/PhysRevB.98.121104

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Electron-phonon coupling in the undoped cuprate YBa2Cu3O6 estimated from Raman and optical conductivity spectra

D. Farina, G. De Filippis, A. S. Mishchenko, N. Nagaosa, Jhih-An Yang, D. Reznik, Th. Wolf, V. Cataudella

DOI 10.1103/PhysRevB.98.121104 · Physical Review B

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Abstract

We study experimentally the Raman response of the undoped high-Tc parent compound YBa2Cu3O6, and give a unified theory of the two-magnon Raman peak and optical conductivity based on the Hubbard-Holstein model with electron-phonon coupling (EPC). The Hubbard model without EPC can qualitatively account for the experimentally observed resonance of the Raman response, but only the Hubbard-Holstein model (i) reproduces the asymmetry of the Raman spectrum, (ii) validates the experimental visibility of the two-magnon peak, and (iii) predicts the correct shape and energy of the lower edge of the charge transfer gap in optical conductivity. A comparison of experiments with the theory gives the EPC strength λ=0.6. This result convincingly indicates the vital role of EPC in high-Tc cuprates, providing a clue to the mechanism of high Tc.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown