We report resistivity ρ and thermal conductivity κ measurements on Ca3Ir4Sn13 single crystals, in which superconductivity with Tc≈7 K was claimed to coexist with ferromagnetic spin-fluctuations. Among three crystals, only one crystal shows a small hump in resistivity near 20 K, which was previously attributed to the ferromagnetic spin-fluctuations. Other two crystals show the ρ∼T2 Fermi-liquid behavior at low temperature. For both single crystals with and without the resistivity anomaly, the residual linear term κ0/T is negligible in zero magnetic field. In low fields, κ0(H)/T shows a slow field dependence. These results demonstrate that the superconducting gap of Ca3Ir4Sn13 is nodeless, thus rule out nodal gap caused by ferromagnetic spin-fluctuations.
@article{arxiv.1202.5164,
title = {Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle heat transport},
author = {S. Y. Zhou and H. Zhang and X. C. Hong and B. Y. Pan and X. Qiu and W. N. Dong and X. L. Li and S. Y. Li},
journal= {arXiv preprint arXiv:1202.5164},
year = {2015}
}