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TT: Fachverband Tiefe Temperaturen

TT 9: SC: Poster Session

TT 9.1: Poster

Montag, 22. März 2010, 14:00–18:00, Poster A

Calorimetry of high-T_c superconductors at different doping levels obtained with ultrafast spectroscopy — •Martin Scheuch^1,3, Luca Perfetti², Tobias Kampfrath³, Christian Frischkorn¹, and Martin Wolf^1,3 — ¹Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin — ²Laboratoire des Solides Irradiés, Ecole polytechnique, 91128 Palaiseau cedex, France — ³Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin

A new approach for obtaining the electronic part of the heat capacity of highly correlated electron systems is discussed. When energy is absorbed from an incident femtosecond laser pulse, it is first deposited in the electronic system of a solid and, subsequently, tranferred to the lattice. Using a THz probe pulse directly after optical excitation, before energy is transferred to the lattice, one can determine the instantaneous temperature of the electrons. This has been done for the high-T_c superconductor Bi₂Sr₂CaCu₂O_8+δ. In combination with time-domain THz spectroscopy at different sample temperatures, the equivalence of photo- and heat-induced conductivity-changes, especially regarding the phase transition, was shown. With this the electronic heat capacity of Bi₂Sr₂CaCu₂O_8+δ was extracted for different doping levels δ.