Possible Sign-Reversing <I>s</I>-Wave Superconductivity in Co-Doped BaFe<SUB>2</SUB>As<SUB>2</SUB> Proved by Thermal Transport Measurements
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Thermal transport measurements have been performed on single-crystalline Co-doped BaFe<SUB>2</SUB>As<SUB>2</SUB> down to 0.1 K and under magnetic fields up to 7 T. Significant peak anomalies are observed in both thermal conductivity and thermal Hall conductivity below <I>T</I><SUB>c</SUB> as an indication of the enhancement of the quasiparticle mean-free path. Moreover, we find a sizable residual <I>T</I>-linear term in thermal conductivity, possibly due to a finite quasiparticle density of states in the superconducting gap induced by impurity pair breaking. Our findings support a pairing symmetry compatible with the theoretically predicted sign-reversing <I>s</I>-wave state.
- Journal of the Physical Society of Japan
Journal of the Physical Society of Japan 78(7), 073705-073705, 2009
THE PHYSICAL SOCIETY OF JAPAN