Field angle dependence of the zero-energy density of states in unconventional superconductors: analysis of the borocarbide superconductor YNi2B2C

TL;DR

This study analyzes how the zero-energy density of states in the unconventional superconductor YNi2B2C varies with magnetic field angle, using realistic band structures and the Kramer-Pesch approximation to reconcile experimental observations.

Contribution

It introduces a detailed analysis of field-angle dependence in YNi2B2C considering multiple bands and improves oscillation amplitude calculations with the Kramer-Pesch approximation.

Findings

Superconducting gap structure aligns with STM, thermal transport, and heat capacity data.

Realistic Fermi surfaces are crucial for accurate DOS analysis.

Kramer-Pesch approximation enhances oscillation amplitude predictions.

Abstract

We investigate the field-angle-dependent zero-energy density of states for YNi2B2C with using realistic Fermi surfaces obtained by band calculations. Both the 17th and 18th bands are taken into account. For calculating the oscillating density of states, we adopt the Kramer-Pesch approximation, which is found to improve accuracy in the oscillation amplitude. We show that superconducting gap structure determined by analyzing STM experiments is consistent with thermal transport and heat capacity measurements.