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

TL;DR

This paper investigates how the spin susceptibility varies with temperature in noncentrosymmetric superconductors with line nodes, revealing distinct convexity behaviors depending on the orientation of the nodes and comparing predictions with experimental data.

Contribution

It provides a detailed analysis of the temperature dependence of spin susceptibility in noncentrosymmetric superconductors with line nodes, including predictions for polycrystalline samples and comparison with experiments.

Findings

Spin susceptibility curve's convexity depends on line node orientation.

Predicted temperature dependence matches experimental Knight shift data.

Distinct behaviors observed for different pairing symmetries.

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.