TY - JOUR
T1 - Discontinuity of the ultrafast electronic response of underdoped superconducting Bi2 Sr2 CaCu2 O8+δ strongly excited by ultrashort light pulses
AU - Giannetti, Claudio
AU - Coslovich, Giacomo
AU - Cilento, Federico
AU - Ferrini, Gabriele
AU - Eisaki, Hiroshi
AU - Kaneko, Nobuhisa
AU - Greven, Martin
AU - Parmigiani, Fulvio
PY - 2009/6/3
Y1 - 2009/6/3
N2 - We report the experimental evidence of an abrupt transition of the ultrafast electronic response of underdoped superconducting Bi2 Sr2 CaCu2 O8+δ, under the impulsive photoinjection of a high density of excitations, using ultrashort laser pulses and avoiding significant laser heating. The direct proof of this process is the discontinuity of the transient optical electronic response, observed at a critical fluence of Φth 70 μJ/ cm2. Below this threshold, the recovery dynamics is described by the Rothwarf-Taylor equations, whereas, above the critical intensity, a fast electronic response is superimposed to a slower dynamics related to the superconductivity recovery. We discuss our experimental findings within the frame of the available models for nonequilibrium superconductivity, i.e., the Teff and μeff models. The measured critical fluence is compatible with a first-order photoinduced phase transition triggered by the impulsive shift of the chemical potential. The measured value, significantly in excess of the condensation energy, indicates that, close to the threshold, the largest amount of energy is delivered to phonons or to other gap-energy excitations strongly coupled to Cooper pairs.
AB - We report the experimental evidence of an abrupt transition of the ultrafast electronic response of underdoped superconducting Bi2 Sr2 CaCu2 O8+δ, under the impulsive photoinjection of a high density of excitations, using ultrashort laser pulses and avoiding significant laser heating. The direct proof of this process is the discontinuity of the transient optical electronic response, observed at a critical fluence of Φth 70 μJ/ cm2. Below this threshold, the recovery dynamics is described by the Rothwarf-Taylor equations, whereas, above the critical intensity, a fast electronic response is superimposed to a slower dynamics related to the superconductivity recovery. We discuss our experimental findings within the frame of the available models for nonequilibrium superconductivity, i.e., the Teff and μeff models. The measured critical fluence is compatible with a first-order photoinduced phase transition triggered by the impulsive shift of the chemical potential. The measured value, significantly in excess of the condensation energy, indicates that, close to the threshold, the largest amount of energy is delivered to phonons or to other gap-energy excitations strongly coupled to Cooper pairs.
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U2 - 10.1103/PhysRevB.79.224502
DO - 10.1103/PhysRevB.79.224502
M3 - Article
AN - SCOPUS:67650151555
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 1098-0121
IS - 22
M1 - 224502
ER -