Hole doping and chemical pressure effects on the strong coupling superconductor PdTe.

Abstract

Chemical doping of known superconductors is a probate strategy to test and enhance our understanding of which parameters control the critical temperature Tc and the critical magnetic fields. The transition metal chalcogenide PdTe is considered a conventional type II superconductor but its resilience to magnetic Fe doping is noteworthy. Isoelectronic Ni doping has been performed, but the effects of doping charges into PdTe have been so far unexplored. We follow two strategies to introduce holes into PdTe and to exert chemical pressure on it: by pnictogen doping on the chalcogen site PdTe1-xSbx and by systematically introducing a Pd deficiency in Pd1-yTe. We find that the superconducting Tc is very sensitive to both kinds of doping. We employ density functional theory to rationalize the observations. We conclude that in PdTe, the effects of charge doping take the lead but we can also identify a structural parameter that correlates with Tc.