1208.1596 (J. Chen et al.)

Evidence for two-gap superconductivity in the non-centrosymmetric
compound LaNiC$_2$    [PDF]

J. Chen, J. L. Zhang, L. Jiao, Y. Chen, L. Yang, M. Nicklas, F. Steglich, H. Q. Yuan

We study the superconducting properties of the non-centrosymmetric compound LaNiC$_2$ by measuring the London penetration depth $\Delta \lambda (T)$, the specific heat $C(T,B)$ and the electrical resistivity $\rho (T,B)$. Both $\Delta\lambda (T)$ and the electronic specific heat $C_e(T)$ exhibit exponential behavior at low temperatures and can be described in terms of a phenomenological two-gap BCS model. The residual Sommerfeld coefficient in the superconducting state, $\gamma_0(B)$, shows a fast increase at low fields and then an eventual saturation with increasing magnetic field. A pronounced upturn curvature is observed in the upper critical field $B_{c2}(T)$ near $T_{c}$. All the experimental observations support the existence of two-gap superconductivity in LaNiC$_2$.

View original: http://arxiv.org/abs/1208.1596