Positions of Point-Nodes in Borocarbide Superconductor YNi2B2C

TL;DR

This study uses theoretical calculations and experimental comparisons to identify the position of point-nodes in the superconducting gap of YNi2B2C, revealing a gap structure with nodes along <110>.

Contribution

It introduces a detailed theoretical analysis of the gap structure in YNi2B2C, matching experimental data to pinpoint the location of point-nodes.

Findings

Point-nodes are located along <110> in YNi2B2C.

The proposed gap structure aligns with angular-resolved experimental results.

The study combines Eilenberger theory and experimental data for gap identification.

Abstract

To determine the superconducting gap function of YNi2B2C, we calculate the local density of states (LDOS) around a single vortex core with the use of Eilenberger theory and the band structure calculated by local density approximation assuming various gap structures with point-nodes at different positions. We also calculate the angular-dependent heat capacity in the vortex state on the basis of the Doppler-Shift method. Comparing our results with the STM/STS experiment, the angular-dependent heat capacity and thermal conductivity, we propose the gap-structure of YNi2B2C, which has the point-nodes and gap minima along <110>. Our gap-structure is consistent with all results of angular-resolved experiments.