STM study of multiband superconductivity in NbSe2 using a superconducting tip

TL;DR

This study develops superconducting tips for STM/STS experiments and uses them to investigate multiband superconductivity in NbSe2 across a range of temperatures, revealing enhanced features in the density of states.

Contribution

It introduces a method to produce superconducting tips for STM/STS and demonstrates their use in revealing multiband superconductivity in NbSe2.

Findings

Enhanced features in tunneling conductance curves due to superconducting tips

Evidence of multiband superconductivity in NbSe2

Temperature-dependent evolution of the electronic density of states

Abstract

We present a method to produce superconducting tips to be used in Scanning Tunneling Microscopy/Spectroscopy experiments. We use these tips to investigate the evolution of the electronic density of states of NbSe2 from 0.3K up to its critical temperature (7.2K). The use of a superconducting tip (Pb) as ounterelectrode provides an enhancement of the different features related to the DOS of NbSe2 in the tunneling conductance curves, along all the studied thermal range. The analysis of the experimental results gives evidence of the presence of multiband superconductivity in NbSe2.