Measuring superconducting arcs by ARPES

TL;DR

This paper demonstrates the use of synchrotron-based ARPES to detect the superconducting gap at surface Fermi arcs in t-PtBi2 under less restrictive conditions, advancing the study of topological superconductors.

Contribution

It introduces a method to observe the superconducting gap in t-PtBi2 using more accessible ARPES setups, expanding experimental capabilities.

Findings

Superconducting gap detected at surface Fermi arcs in t-PtBi2.

Synchrotron-based ARPES effective under relaxed conditions.

Model identifies minimal requirements for gap detection.

Abstract

Angle-resolved photoemission spectroscopy is the leading tool for studying the symmetry and structure of the order parameter in superconductors. The recent improvement of the technique made it possible to detect the superconducting energy gap at the surface of topological t-PtBi2 via observation of the record-breaking narrow line shapes. The promising new physics uncovered requires further investigation of the spectral and gap functions of t-PtBi2, but the challenging experimental conditions severely limit the application of conventional ARPES setups. In this work, we use synchrotron-based measurements and show that the gap at the surface Fermi arc in t-PtBi2 can be detected even with more relaxed experimental conditions than in our previous laser-based studies. At the same time, using simple model of ARPES spectra, we identify the minimum requirements to detect the gap and consider cases where the gap cannot be resolved.