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

TL;DR

This study shows that increasing disorder in PdTe$_2$ via Pt doping induces a transition from type-I to type-II superconductivity, with a specific residual resistivity threshold identified.

Contribution

It demonstrates experimentally how disorder can induce a transition from type-I to type-II superconductivity in PdTe$_2$ through controlled doping.

Findings

Disorder induces a transition from type-I to type-II superconductivity.

Residual resistivity of 1.4 μΩcm triggers the transition.

Pt doping results in non-homogeneous distribution and non-stoichiometric compositions.

Abstract

We report a doping study directed to intentionally induce disorder in PdTe$_2$ by the isoelectronic substitution of Pt. Two single-crystalline batches Pd$_{1-x}$Pt$_x$Te$_2$ 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 Pd$_{0.97}$Pt$_{<0.004}$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 $\rho_0$ = 1.4 $\mu$$\Omega$cm suffices to turn PdTe$_2$ into a superconductor of the second kind.