Superfluid Density and Energy Gap-Function of Superconducting PrPt4Ge12

TL;DR

This study investigates the superconducting properties of PrPt4Ge12, revealing point-like nodes in its energy gap and providing detailed measurements of its superfluid density and gap structure using muSR and specific heat experiments.

Contribution

It presents the first detailed analysis of the superfluid density and energy gap structure of PrPt4Ge12, identifying point-like nodes and specific gap functional forms.

Findings

Superfluid density increases continuously with decreasing temperature.

Electronic specific heat shows a T^3 dependence, indicating point-like nodes.

Energy gap ratios suggest strong coupling superconductivity.

Abstract

The filled skutterudite superconductor PrPt4Ge12 was studied in muon-spin rotation (muSR), specific heat, and electrical resistivity experiments. The continuous increase of the superfluid density with decreasing temperature and the dependence of the magnetic penetration depth \lambda on the magnetic field obtained by means of muSR, as well as the observation of a T^3 dependence of the electronic specific heat establish the presence of point-like nodes in the superconducting energy gap. The energy gap was found to be well described by \Delta =\Delta_0| k_x - ik_y| or \Delta = \Delta_0(1 - k_y^4) functional forms, similar to that obtained for another skutterudite superconductor, PrOs4Sb12. The gap to T_c ratios were estimated to be \Delta_0/k_BT_c = 2.68(5) and 2.29(5), respectively.