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Heat Conduction in the Vortex State of NbSe_2: Evidence for Multi-Band Superconductivity

Etienne Boaknin·M. A. Tanatar·Johnpierre Paglione·D. Hawthorn·F. Ronning·R. W. Hill·M. Sutherland·Louis Taillefer·Jeff Sonier·S. M. Hayden·J. W. Brill
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Abstract

The thermal conductivity kappa of the layered s-wave superconductor NbSe_2 was measured down to T_c/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H_c1 and one with highly delocalized quasiparticle excitations at higher fields. The two associated length scales are naturally explained as multi-band superconductivity, with distinct small and large superconducting gaps on different sheets of the Fermi surface. This behavior is compared to that of the multi-band superconductor MgB_2 and the conventional superconductor V_3Si.

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Etienne Boaknin, M. A. Tanatar, Johnpierre Paglione, D. Hawthorn, F. Ronning, R. W. Hill, M. Sutherland, Louis Taillefer, Jeff Sonier, S. M. Hayden, J. W. Brill. 2003-03-18. Heat Conduction in the Vortex State of NbSe_2: Evidence for Multi-Band Superconductivity. https://doi.org/10.1103/physrevlett.90.117003

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