Strong enhancement of superconductivity at high pressures within the   charge-density-wave states of 2H-TaS 2 and 2H-TaSe 2
  We present measurements of the superconducting and charge density wave critical temperatures (Tc and TCDW) as a function of pressure in the transition metal dichalchogenides 2H-TaSe2 and 2H-TaS2. Resistance and susceptibility measurements show that Tc increases from temperatures below 1 K up to 8.5 K at 9.5 GPa in 2H-TaS2 and 8.2 K at 23 GPa in 2H-TaSe2. We observe a kink in the pressure dependence of TCDW at about 4 GPa that we attribute to the lock-in transition from incommensurate CDW to commensurate CDW. Above this pressure, the commensurate TCDW slowly decreases coexisting with superconductivity within our full pressure range. 
D.C. Freitas, P Rodiere, M.R. Osorio, E Navarro-Moratalla (ICMol),   N.M. Nemes, V.G. Tissen, L Cario (IMN), E Coronado (IIA...
cond-mat.supr-con cond-mat.str-el