Analysis of field-angle dependent specific heat in unconventional superconductors: a comparison between Doppler-shift method and Kramer-Pesch approximation

TL;DR

This paper compares the Doppler-shift method and Kramer-Pesch approximation for analyzing the magnetic-field-angle dependence of zero-energy density of states in unconventional superconductors, highlighting corrections provided by KPA.

Contribution

It introduces a detailed comparison between DS and KPA methods, demonstrating how KPA corrects and improves upon DS calculations for ZEDOS in superconductors.

Findings

KPA provides corrections to DS results.

Both methods are applied to different Fermi surface geometries.

KPA enhances the accuracy of ZEDOS predictions.

Abstract

We theoretically discuss the magnetic-field-angle dependence of the zero-energy density of states (ZEDOS) in superconductors. Point-node and line-node superconducting gaps on spherical and cylindrical Fermi surfaces are considered. The Doppler-shift (DS) method and the Kramer-Pesch approximation (KPA) are used to calculate the ZEDOS. Numerical results show that consequences of the DS method are corrected by the KPA.