Pressure effects on the charge-density-wave phases in 2 H-TaSe2

The transition temperatures from the commensurate to incommensurate phase (Td) and from the incommensurate to normal phase (T0) in 2 H-TaSe2 have been determined as a function of hydrostatic pressure up to 18 kbar. We found that while T0 increases only slightly with pressure, Td falls rapidly as (1-PPc)12 under pressure, extrapolating to a critical pressure Pc of 17 kbar for the complete stabilization of the incommensurate phase. We conclude that the interlayer coupling can not be neglected in discussing the stability of the charge-density-wave state.