Thickness Dependence of Superconductivity in Layered Topological Superconductor β-PdBi2

Abstract

We report a systematic study on the thickness-dependent superconductivity and transport properties in exfoliated layered topological superconductor <i>β</i>-PdBi₂. The superconducting transition temperature <i>T</i>_c is found to decrease with the decreasing thickness. Below a critical thickness of 45 nm, the superconductivity is suppressed, but followed by an abrupt resistance jump near <i>T</i>_c, which is in opposite to the behavior in a superconductor. We attribute suppressed <i>T</i>_c to the enhanced disorder as the thickness decreases. The possible physical mechanisms were discussed for the origination of sharply increased resistance in thinner <i>β</i>-PdBi₂ samples.