Point-contact spectra of $2H-NbS{{e}_{2}}$ in the superconducting state

TL;DR

This study investigates the electron-phonon interaction spectra in 2H-NbSe2 using point-contact spectroscopy, revealing anisotropy and features related to charge density waves in the superconducting state.

Contribution

It provides the first qualitative analysis of EPI spectra in 2H-NbSe2 in the superconducting state, highlighting anisotropic features and their relation to charge density waves.

Findings

Anisotropic EPI spectra observed along different crystallographic directions.

Main phonon features identified in the density of states.

Low-frequency peaks linked to charge density wave oscillations.

Abstract

A qualitative study of the electron-phonon interaction (EPI) spectra in $2H-NbS{{e}_{2}}$ is carried out by the method of point-contact spectroscopy in the superconducting state. Anisotropy of the EPI spectra for contacts oriented in the principal crystallographic directions (along the $c$ axis and parallel to the basal surface) was observed. Approximate values of the positions of the main features in the phonon density of states were established for both directions. The additional low-frequency peaks observed in the spectra for separate crystallographic orientations are associated with the collective oscillations of the amplitude and phase of charge density waves.