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キーワード:
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要旨:
The magnitude and the temperature dependence of the superconducting order parameter Delta(T) of single crystals of Cd2Re2O7 (T-c = 1.02 K) was measured using point-contact spectroscopy. To fit the conductance spectra and to extract the order parameter at different temperatures we generalized the Blonder-Tinkham-Klapwijk theory by including the self-energy of the quasiparticles into the Bogoliubov equations. This modification enabled excellent fits of the conductance spectra. Delta(T) increases steeply below the superconducting transition temperature of 1.02 K and levels off below similar to 0.8 K at a value of 0.22(1) meV, approximate to 40% larger than the BCS value. Our results indicate the presence of a strong electron-phonon interaction and an enhanced quasiparticle damping and may be related to a possible phase transition within the superconducting region at similar to 0.8 K.
