Theoretical analysis of anisotropic upper critical field of superconductivity in nodal-line semimetals

TL;DR

This paper provides a theoretical analysis of the anisotropic upper critical field in nodal-line semimetals, revealing large anisotropy and unusual temperature dependence, with implications for understanding superconductivity in these materials.

Contribution

It introduces a continuous model and semiclassical Green's function method to analyze the upper critical field in nodal-line semimetals, considering both dirty and clean limits, and compares results with experimental data.

Findings

Large anisotropy in upper critical field magnitude

Unusual temperature dependence of the critical field

Agreement with experimental data of PbTaSe2

Abstract

We study the properties of the upper critical field of superconductivity in nodal-line semimetals in a continuous model, which has a nodal-line on the $k_{z} = 0$ plane. Using the semiclassical Green's function method, we calculate the upper critical field for the two limiting cases: the dirty limit with many impurities and the clean limit with few impurities. The results show the large anisotropy of the magnitude of the upper critical field and the unusual temperature dependence. The obtained results are compared with recent experimental data of PbTaSe$_{2}$.