Disorder induced transition from type-I to type-II superconductivity in the Dirac semimetal PdTe$_2$

Abstract

We report a doping study directed to intentionally induce disorder in PdTe2 by the isoelectronic substitution of Pt. Two single-crystalline batches Pd1−xPtxTe2 have been prepared with nominal doping concentrations x = 0.05 and x = 0.10. Sample characterization by energy dispersive x-ray spectroscopy (EDX) revealed Pt did not dissolve homogeneously in the crystals. For the nominal value x = 0.10 small single crystals cut from the batch appeared to have x = 0.09, as well as the non stoichiometric composition Pd0.97Pt<0.004Te2.03. Magnetic and heat capacity measurements demonstrate a transition from type-I to type-II superconducting behavior upon increasing disorder. From transport measurements we calculate a residual resistivity ρ0 = 1.4 µΩcm suffices to turn PdTe2 into a superconductor of the second kind.