Ultrafast carrier relaxation dynamics in single-layer cuprates

¹ Physics Department, University of Wisconsin-Madison - Madison, WI 53706, USA
² Los Alamos National Laboratory - Los Alamos, NM, USA
³ Physics Department, Vanderbilt University - Nashville, TN, USA
⁴ Institute of Physics, Polish Academy of Sciences - PL-02904 Warszawa, Poland
⁵ Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester - Rochester, NY 14627, USA
⁶ Humboldt-Universität, Institut für Physik - Invalidenstrasse 110 D-10115 Berlin, Germany
⁷ Applied Sciences Department, College of William and Mary - Williamsburg, VA, USA
⁸ Physics Department, Pennsylvania State University - University Park, PA, USA
⁹ OXXEL GmbH, Technologiepark Universitaet - Fahrenheitstrasse 9 Bremen, D-28359, Germany

Received: 22 April 2002
Accepted: 22 August 2002

Abstract

Using a femtosecond pump-probe optical technique, we measured the time-resolv ed change in reflectivity of three single-layer cuprate samples, including _x , and _x grown on . We analyze the data in terms of a nonthermal electron relaxation model, and obtain quantitative agreement between the model and the data. The initial electron-electron thermalization process is much longer in the superconducting samples as opposed to the overdoped nonsuperconducting sample, suggesting a bottleneck in electron thermalization process due to the presence of the superconducting gap.