Observation of Andreev bound state and multiple energy gaps in the non-centrosymmetric superconductor BiPd

TL;DR

This study uses point contact Andreev reflection to reveal multiple energy gaps and signs of unconventional superconductivity in high-quality BiPd crystals, advancing understanding of non-centrosymmetric superconductors.

Contribution

It provides direct experimental evidence of multiple superconducting gaps and unconventional order parameters in BiPd through directional PCAR measurements.

Findings

Multiple superconducting energy gaps observed.

Pronounced zero bias conductance peak detected.

Evidence of unconventional superconductivity in BiPd.

Abstract

We report directional point contact Andreev reflection (PCAR) measurements on high-quality single crystals of the non-centrosymmetric superconductor, BiPd. The PCAR spectra measured on different crystallographic faces of the single crystal clearly show the presence of multiple superconducting energy gaps. For point contacts with low resistance, in addition to the superconducting gap feature, a pronounced zero bias conductance peak is observed. These observations provide strong evidence of the presence of unconventional order parameter in this material.