Point Contact Spectroscopy of Nb3Sn Crystals: Evidence of a CDW Gap Related to the Martensitic Transition

TL;DR

This study uses point contact spectroscopy on Nb3Sn crystals to investigate electronic density of states changes associated with the martensitic transition, revealing evidence of a charge density wave gap.

Contribution

It provides new spectroscopic evidence linking the martensitic anomaly in Nb3Sn to a charge density wave gap, highlighting the influence of crystal structure.

Findings

Observation of a charge density wave gap associated with the martensitic transition.

Spectroscopic features vary with crystallographic characteristics.

Evidence of electronic density of states changes across the transition.

Abstract

Two Single crystals of Nb3Sn presenting the martensitic anomaly at different temperature and shape, as observed with specific heat measurements, were used to study structural features in the electronic density of states with point contact spectroscopy. At high temperature below the martensitic anomaly, we observed different spectroscopic characteristics. One sample displaying a well marked specific heat peak, shows a clear defined structure in the differential conductance that evolves with temperature and may be associated with changes on the density of states due to the opening of a charge density wave gap. Those features are very depending on the crystallographics characteristics of the single crystal examined.