Disorder-induced transition from type-I to type-II superconductivity in the Dirac semimetal PdTe2

Abstract

We report a doping study directed to intentionally induce disorder in ${\mathrm{PdTe}}_{2}$ by the isoelectronic substitution of Pt. Two single-crystalline batches ${\mathrm{Pd}}_{1\ensuremath{-}x}{\mathrm{Pt}}_{x}{\mathrm{Te}}_{2}$ have been prepared with nominal doping concentrations $x=0.05$ and $x=0.10$. Sample characterization by energy dispersive x-ray spectroscopy 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 nonstoichiometric composition ${\mathrm{Pd}}_{0.97}{\mathrm{Pt}}_{<0.004}{\mathrm{Te}}_{2.03}$. 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 ${\ensuremath{\rho}}_{0}=1.4\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{\ensuremath{\Omega}}\phantom{\rule{0.16em}{0ex}}\mathrm{cm}$ suffices to turn ${\mathrm{PdTe}}_{2}$ into a superconductor of the second kind.