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Spatially-resolved relaxation dynamics of photoinduced quasiparticles in underdoped YBa$sub 2$Cu$sub 3$O$sub {7-delta}$

C. W. Luo·P. T. Shih·Y. -J. Chen·M. H. Chen·K. H. Wu·J. Y. Juang·J. -Y. Lin·T. M. Uen·Y. S. Gou
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Abstract

The spatially-resolved relaxation characteristics of photoinduced quasiparticles (QPs) in CuO$sub 2$ planes of underdoped YBCO are disclosed by polarized fs time-resolved spectroscopy. The relaxation time (tau) along b axis diverges at Tc, and appears to be governed by a temperature-dependent gap Delta(T) at T < Tc. Furthermore, for T > Tc, a monotonic increase of tau with decreasing T along the b axis and ab diagonal was observed and can be attributed to a temperature-independent gap Delta$sub p$. The results lend support to recombination dominant scenario of QP dynamics. However, the QP thermalization may take part along the nodal direction in the highly underdoped samples.

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C. W. Luo, P. T. Shih, Y. -J. Chen, M. H. Chen, K. H. Wu, J. Y. Juang, J. -Y. Lin, T. M. Uen, Y. S. Gou. 2005-08-20. Spatially-resolved relaxation dynamics of photoinduced quasiparticles in underdoped YBa$sub 2$Cu$sub 3$O$sub {7-delta}$. https://doi.org/10.1103/physrevb.72.092506

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