title: High-temperature optical spectral weight and fermi-liquid renormalization in bi-based cuprate superconductors.
abstract: The optical conductivity σ(ω) and the spectral weight W(T) of two superconducting cuprates at optimum doping, Bi2Sr2-xLaxCuO6 and Bi2Sr2CaCu2O8, have been first measured up to 500 K. Above 300 K, W(T) deviates from the usual T2 behavior in both compounds, even though σ(ω→0) remains larger than the Ioffe-Regel limit. The deviation is surprisingly well described by the T4 term of the Sommerfeld expansion, but its coefficients are enhanced by strong correlation, as shown by the good agreement with dynamical mean field calculations.
authors.affiliation: CNR-SPIN and Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale A. Moro 2, I-00185 Roma, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Nicoletti
authors.forename: O
authors.initials: O
authors.lastname: Limaj
authors.forename: P
authors.initials: P
authors.lastname: Calvani
authors.forename: G
authors.initials: G
authors.lastname: Rohringer
authors.forename: A
authors.initials: A
authors.lastname: Toschi
authors.forename: G
authors.initials: G
authors.lastname: Sangiovanni
authors.forename: M
authors.initials: M
authors.lastname: Capone
authors.forename: K
authors.initials: K
authors.lastname: Held
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ando
authors.forename: S
authors.initials: S
authors.lastname: Lupi