Evolution of charge density wave order and superconductivity under pressure in LaPt2Si2
Abstract
We report measurements of the electrical resistivity and ac magnetic susceptibility of single crystalline LaPt2Si2 under pressure, in order to investigate the interplay of superconductivity and CDW order. LaPt2Si2 exhibits a first order phase transition from a tetragonal to orthorhombic structure, accompanied by the onset of CDW order below TCDW = 76 K, while superconductivity occurs at a lower temperature of Tc = 1.87 K. We find that the application of pressure initially suppresses the CDW transition, but enhances Tc. At pressures above 2.4 GPa, CDW order vanishes, while both Tc and the resistivity A-coefficient reach a maximum value around this pressure. Our results suggest that the occurrence of a superconducting dome can be accounted for within the framework of BCS theory, where there is a maximum in the density of states upon the closure of the CDW gap.