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VOLUME 59 (1994) | ISSUE 11 |
PAGE 754
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Possibility of a power temperature dependence of the low-temperature penetration depth in an S-wave superconductor
Klimovitch G.V.
A number of experimental measurements of λ in HTSC have revealed a power temperature dependence of (λ(Γ) λ(0)) at Τ < Tc, which is often considered as an unambiguous evidence of gap nodes, and ascribed to unconventional pairing. However, electron coupling to the low-lying excitations with energy ~ Τ always gives rise to a power dependence of λ(Γ) even for an S-wave superconductors without gap zeros. Negligible in conventional superconductors, this effect may be large enough to be observed experimentally in high-Tc compounds. Thus, power dependence of (λ(Γ) λ(0)) does not exclude S-coupling. In particular, linear and quadratic temperature dependences of λ may occur. Besides analytical results, a calculational illustration is presented.
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