Ultrafast Dynamics of Photoinduced Electronic Phase Modulation in Ladder Cuprate of Sr_{14 - x}Ca_xCu₂₄O₄₁

Abstract

Ultrafast carrier dynamics caused by photoexcitation in quasi-one-dimensional two-leg ladder cuprate Sr4Ca10Cu24O41 was investigated by the femtosecond reflection spectroscopy. After the photoexcitation along the leg direction, the transient reflectivity changes (∆R/R) in the mid-infrared region showed instant decrease within 150 fs. The suppressed ∆R/R increased so rapidly on the picosecond time scale that the reflectivity value finally became larger than that in the initial state. Such a successive response in ∆R/R, which was also observed in other photon energy regions, is discussed in terms of ultrafast variation of the Drude weight in the ladder system by the photoirradiation.

Photoinduced correlated electron dynamics in a two-leg ladder Hubbard system

“…18,20,23,47 The time resolved optical experiments were also performed in the metallic ladder cuprates, Sr 14−x Ca x Cu 24 O 41 with x = 10. 36,37 The pump photon energy was tuned at 1.58eV corresponding to the charge transfer excitation energy in the ladder plane. Just after the photon pumping, the low energy optical reflectivity at 0.5eV shows a reduction, implying a suppression of an initial metallic character.…”

“…[29][30][31][32][33][34] Recently, the photoinduced transient states were examined in the insulating (x = 0) and metallic (x = 10) two-leg ladder cuprates by utilizing the ultrafast optical pump-probe experiments. [35][36][37] The transient optical measurements provide a hint to reveal unique spin and charge dynamics as well as their roles on the superconductivity in the two-leg ladder cuprates.…”