Suppression of charge-density wave order in 2H-TaSe2 by pressure

It is now evident that many materials feature superconducting phases when a CDW phase is suppressed by extrinsic parameters such as pressure or intercalation in layered materials. However, studies in transition-metal dichalcogenides (TMDC) found that the phase space of emergent superconductivity is not close to the CDW quantum critical point. Here, we propose to determine the CDW quantum critical point in 2H-TaSe2 under pressure via x-ray diffraction (XRD). Based on our ambient-pressure study of the soft phonon mode at the CDW transition in 2H-TaSe2 (unpublished) and published resistivity measurements, we argue that this compound likely has a CDW quantum critical point closely connected to the emergent superconducting phase and could be a textbook example where both phases are mediated by the same mechanism, electron-phonon coupling of the CDW soft phonon mode. Our study will determine the CDW phase diagram in its most crucial but still unexplored area.