Abstract
We present a detailed investigation of the dynamics of laser-excited quasiparticles in YBa2Cu3O7 thin films below the critical temperature. Reflectivity transients at low temperature trace the generation and recombination behavior of quasiparticles. The quasiparticle cascading and recombination rates are determined by comparison with a detailed nonlinear model of the quasiparticle dynamics based on extended Rothwarf-Taylor equations.
References
D.N. Langenberg: Festkörperprobleme, in Advances in Solid State Physics, Vol.14 (Vieweg, Braunschweig 1974) p.67
J.J. Chang: in Non-Equilibrium Superconductivity, Phonons, and Kapitza Boundaries ed. by K.E. Gray (Plenum, New York 1980) p.263
S.B. Kaplan, et al.: Phys. Rev. B 14, 4854 (1976)
C.C. Chi, M.M.T. Loy, D.C. Cronemeyer: Phys. Rev. B 23, 124 (1981)
M. Johnson: Appl. Phys. Lett. 59, 1371 (1991)
M. Johnson, N. Bluzer, M. Reyser, T.H. Geballe, S.R. Greenfield, J.J. Stankus, M.D. Fayer, C. Herring: IEEE Trans. Mag-27, 1523 (1991)
N. Bluzer: Phys. Rev. B 44, 10222 (1991)
A.D. Semenov, G.N. Goltsman, I.G. Gogidze, A.V. Sergeev, E.M. Gershenzon, P.T. Lang, K.F. Renk: Appl. Phys. Lett. 60, 903 (1992)
H.E. Elsayed-Ali, T.B. Norris, M.A. Pessot, G.A. Mourou: Phys. Rev. Lett. 53, 1857 (1984)
R.W. Schoenlein, W.Z. Lin, J.G. Fujimoto, G.L. Eesley: Phys. Rev. Lett. 58, 1680 (1987)
S.D. Brorson, A. Kazeroonian, D.W. Face, T.K. Cheng, G.L. Doll, M.S. Dresselhaus, G. Dresselhaus, E.P. Ippen, T. Venkatesan, X.D. Wu, A. Inam: Phys. Rev. Lett. 64, 2172 (1990)
S.D. Brorson, A. Kazeroonian, J.S. Modera, D.W. Face, T.K. Cheng, E.P. Ippen, M.S. Dresselhaus, G. Dresselhaus: Solid State Commun. 74, 1305 (1990)
J.M. Chwalek, C. Uher, J.F. Whitaker, G.A. Mourou, J.A. Agnostelli: Appl. Phys. Lett. 57, 1696 (1990)
A.S. Kazeroonian, T.K. Cheng, S.D. Brorson, Q. Li, E.P. Ippen, X.D. Wu, T. Venkatesan, E. Etemad, M.S. Dresselhaus, G. Dresselhaus: Solid State Commun. 78, 95 (1991)
S.G. Han, Z.V. Vardeny, K.S. Wong, O.G. Symko: Phys. Rev. Lett. 65, 2078 (1990)
G.L. Eesley, J. Heremans, M.S. Meyer, G.L. Doll: Phys. Rev. Lett. 65, 3445 (1990)
D.H. Reitze, A.M. Weiner, A. Inam, S. Etermad: Phys. Rev. B 46, 14309 (1992)
The 50 fs laser pulses are broadened to about 80 fs due to dispersion in the cryostat windows
M. Strahnen, W. Kütt, H. Kurz: In VME Bus in Research (Elsevier, Amsterdam 1988)
The traces have a weak modulation caused by the excitation of coherent phonon oscillations, which have been discussed elsewhere [W. Albrecht, T. Kruse, H. Kurz: Phys. Rev. Lett. 69, 1451 (1992)]. Coherent phonon oscillations have also been observed in non-superconducting YBa2Cu3O7-δ [J.M. Chwalek, et al.: Appl. Phys. Lett. 58, 980 (1991)]
M. Tinkham: Introduction to Superconductivity (Robert E. Grieger, Malabar, Fl 1975)
W. Albrecht, T. Kruse, K. Leo, H. Kurz: Appl. Phys. A 56, 469 (1993)
A similar inversion is observed for lower laser energies
A. Rothwarf, B.N. Taylor: Phys. Rev. Lett. 19, 27 (1967)
The fit exhibits only a weak dependence on τb, thus limiting its accuracy. However, the value of 10 fs is in reasonable agreement with the theoretical expectation of 57 fs, as calculated in [7] from the theory of [3]. The estimated error of the other fit parameters is about 30%. The overall precision is obviously strongly dependent on the estimated density of photogenerated QP
Eesley, et al. [16] obtain in Tl2Ba2Ca2Cu3O10 a density-independent behavior at comparable QP densities. The reason for this discrepancy to our results is not clear.
I. Schuller, K.E. Gray: Phys. Rev. Lett. 36, 429 (1976)
K.E. Gray: J. Phys. F I, 290 (1971)
B. Friedl, C. Thomsen, M. Cardona: Phys. Rev. Lett. 65, 915 (1990)