Charge Density Waves and the Effects of Uniaxial Strain on the Electronic Structure of 2H-NbSe$_2$

TL;DR

This study uses angle-resolved photoemission spectroscopy to reveal hidden charge density wave signatures in 2H-NbSe2 and shows how uniaxial strain significantly alters its electronic structure and symmetry.

Contribution

It uncovers previously undetected charge density wave features and demonstrates the impact of uniaxial strain on the electronic structure of 2H-NbSe2.

Findings

Detected new charge density wave signatures on the Fermi surface.

Uniaxial strain causes substantial electronic structure changes.

Strain lowers symmetry and affects charge density wave and superconductivity.

Abstract

Interplay of superconductivity and density wave orders has been at the forefront of research of correlated electronic phases for a long time. 2H-NbSe$_2$ is considered to be a prototype system for studying this interplay, where the balance between the two orders was proven to be sensitive to band filling and pressure. However, the origin of charge density wave in this material is still unresolved. Here, by using angle-resolved photoemission spectroscopy, we revisit the charge density wave order and study the effects of uniaxial strain on the electronic structure of 2H-NbSe$_2$. Our results indicate previously undetected signatures of charge density waves on the Fermi surface. The application of small amount of uniaxial strain induces substantial changes in the electronic structure and lowers its symmetry. This, and the altered lattice should affect both the charge density wave phase and superconductivity and should be observable in the macroscopic properties.