The superconducting gap structure of recently discovered heavy fermion CePt_3Si without spatial inversion symmetry was investigated by thermal transport measurements down to 40 mK. In zero field a residual T-linear term was clearly resolved as T-> 0, with a magnitude in good agreement with the value expected for a residual normal fluid with a nodal gap structure, together with a T^2-dependence at high temperatures. With an applied magnetic fields, the thermal conductivity grows rapidly, in dramatic contrast to fully gapped superconductors, and exhibits one-parameter scaling with T/sqrt{H}. These results place an important constraint on the order parameter symmetry, that is CePt_3Si is most likely to have line nodes.
@article{arxiv.cond-mat/0504350,
title = {Line nodes in the superconducting gap function of noncentrosymmetric CePt_3Si},
author = {K. Izawa and Y. Kasahara and Y. Matsuda and K. Behnia and T. Yasuda and R. Settai and Y. Onuki},
journal= {arXiv preprint arXiv:cond-mat/0504350},
year = {2009}
}
Comments
5pages, 3figures, accpted for publication in Phys. Rev. Lett