Signature of point nodal superconductivity in the Dirac semimetal PdTe

TL;DR

This study provides evidence that PdTe, a Dirac semimetal superconductor, exhibits unconventional superconductivity with point nodes in its gap structure, revealed through specific heat measurements under magnetic fields.

Contribution

The paper demonstrates the presence of bulk point nodes in PdTe's superconducting gap using detailed specific heat measurements, indicating unconventional topological superconductivity.

Findings

Power-law magnetic field dependence of specific heat

Cubic temperature dependence of zero-field specific heat

Evidence of bulk point nodes in PdTe

Abstract

Recent Angle-Resolved Photo-emission Spectroscopy (ARPES) experiments [Phys. Rev. Lett. 130, 046402 (2023)] on PdTe, a 3D-Dirac semimetal and a superconductor with the transition temperature Tc ~ 4.3 K, have revealed compelling evidence of the presence of bulk nodes in the superconducting order parameter. To investigate the validity of this proposition, here we present a detailed investigation of the magnetic field dependence of the specific heat of PdTe down to temperatures ~ 58 mK. We observed that the low temperature specific heat of PdTe with an externally applied magnetic field exhibits a power-law field dependence, a characteristic of unconventional superconductivity. Furthermore, the zero-field low-temperature electronic specific heat follows a cubic temperature dependence, which is a signature of the presence of bulk point nodes in PdTe. These intriguing observations suggest that PdTe is a rare and fascinating topological material that exhibits both Dirac semimetallic properties and superconductivity with point nodal gap symmetry.