Temperature Dependence of the Spin Susceptibility in Noncentrosymmetric Superconductors with Line Nodes

Abstract

The spin susceptibility of noncentrosymmetric superconductors is studied when the gap function has line nodes. As examples, d-wave states, where the gap function has an additional odd-parity phase factor, are examined. The curve of the spin susceptibility $\chi(T)$ is upward convex when all line nodes are parallel to the magnetic field, while it is downward convex in the other d-wave states and an s-wave state. For polycrystalline powder samples, the temperature dependences of $\chi(T)$ are predicted by assuming three explicit conditions of the powder particles. The results are compared with the experimental data of the Knight shift observed in Li_2Pt_3B and Li_2Pd_3B.