Evolution of charge density wave order and superconductivity under pressure in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>LaPt</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Si</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Bin Shen, Feng Du, Rui Li, A. Thamizhavel, M. Smidman, Z. Y. Nie, Shuaishuai Luo, Tian Le, Z. Hossain, Huiqiu Yuan
Abstract
We report measurements of the electrical resistivity and ac magnetic susceptibility of single-crystalline ${\mathrm{LaPt}}_{2}{\mathrm{Si}}_{2}$ under pressure, in order to investigate the interplay of superconductivity and charge density wave (CDW) order. ${\mathrm{LaPt}}_{2}{\mathrm{Si}}_{2}$ exhibits a first-order phase transition from a tetragonal to orthorhombic structure, accompanied by the onset of CDW order below ${T}_{\mathrm{CDW}}$ = 76 K, while superconductivity occurs at a lower temperature of ${T}_{\mathrm{c}}$ = 1.87 K. We find that the application of pressure initially suppresses the CDW transition, but enhances ${T}_{\mathrm{c}}$. At pressures above 2.4 GPa, CDW order vanishes, while both ${T}_{\mathrm{c}}$ 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.