High pressure Low temperature phase diagram of the multiple CDWs systems RPt2Si2 (R=La, Pr)

The RPt2Si2 (with R = La, Pr) single crystals have a complex low-temperature phase diagram. LaPt2Si2 shows at ambient pressure 2 charge density waves phases (200K and 110K) and a tetragonal orthorhombic distortion. A sharp first order anomaly is observed by resistivity measurements at T*~85K often associated to the CDW. Below 1.8K, LaPt2Si2 is a superconductor. Under pressure, resistivity measurements show a disappearance of the first order anomaly at a critical pressure of 2.5GPa. Similarly, PrPt2Si2, show 2 transitions by resistivity measurements, with one of them associated to charge density waves phase. The aim of this proposal is to establish the (P,T) phase diagram and the evolution of the modulation vectors under hydrostatic pressure (up to 10GPa and down to 10K).