Penetration depth study of the type-I superconductor PdTe2

TL;DR

This study measures the magnetic penetration depth in PdTe2, confirming its fully-gapped, weakly-coupled type-I superconducting nature and providing detailed experimental data on its superconducting properties.

Contribution

First precise measurement of the penetration depth in PdTe2, confirming its type-I superconductivity and elucidating its superconducting gap characteristics.

Findings

Exponential temperature dependence of penetration depth below 0.4 T_c

Estimated zero-temperature penetration depth of ~500 nm

Superfluid density matches nonlocal electrodynamics for type-I superconductors

Abstract

Superconductivity in the topological non-trivial Dirac semimetal PdTe$_2$ was recently shown to be type-I. We here report measurements of the relative magnetic penetration depth, $ \Delta \lambda$, on several single crystals using a high precision tunnel diode oscillator technique. The temperature variation $\Delta \lambda (T)$ follows an exponential function for $T/T_c < 0.4$, consistent with a fully-gapped superconducting state and weak or moderately coupling superconductivity. By fitting the data we extract a $\lambda (0)$-value of $\sim 500$~nm. The normalized superfluid density is in good agreement with the computed curve for a type-I superconductor with nonlocal electrodynamics. Small steps are observed in $\Delta \lambda (T)$, which possibly relates to a locally lower $T_c$ due to defects in the single crystalline sample. single crystalline sample.