Superconductivity in LaPd2As2 with a collapsed 122 structure

The superconducting properties of LaPd2As2 with a collapsed tetragonal structure are reported. DC magnetization and resistivity measurements reveal that the compound is a type-II bulk superconductor below 1 K. The electronic specific heat coefficient γ is found to be 5.56 mJ mol−1 K−2. The specific heat change at the superconducting transition is 1.17, which is relatively low compared to the BCS weak coupling limit of 1.43. The density of states at the Fermi level calculated from electronic specific heat data is about 0.84 states/(eV f.u.), which may explain the low Tc of this material. These results, together with previous work on A2+M2X2 compounds, imply that the superconducting transition temperature can be tailored by proper chemical substitution.