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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(Τ) — λ(0)] at T<^TC, which is often considered as an unambiguous evidence of the existence of gap nodes, and which is attributed to unconventional pairing. However, electron coupling to the low-lying excitations with an energy 5Γ always gives rise to a power dependence of λ(Τ) even for S-wave superconductors without gap zeros. Negligible in conventional superconductors, this effect may be large enough to be observed experimentally in high-7^. 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. A calculational illustration is presented, in addition to the analytical results.
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