Investigation of strain effects in the charge density waves of $2H$-NbSe$_2$

The transition metal dichalcogenide $2H$-NbSe$_2$ possesses coexisting superconducting and charge density wave (CDW) ordered states, which possibly compete below the critical transition temperature, $\sim$7.2K. Previous studies of this system have seen that the CDW is very susceptible to alterations due to local strain. This suggests proximity to a quantum critical point. In this study, we use scanning tunneling microscopy and spectroscopy to investigate the intimate relationship between mechanical strain and the electronic properties of $2H$-NbSe$_2$, and observe the evolution of electronic states on atomic length scales.