Type-I superconductivity in the Dirac semimetal PdTe2 probed by μSR

The Dirac semimetal PdTe2 was recently reported to be a type-I superconductor with T-c = 1.64 K and a critical field mu H-0(c) = 13.6 mT. Since type-I superconductivity is unexpected for binary compounds, we have conducted muon spin rotation (mu SR) experiments to probe the superconducting phase on the microscopic scale via its intermediate state. For crystals with a finite demagnetization factor N, the intermediate state forms in applied fields (1 - N)H-c < H-a < H-c. We have carried out transverse field muon spin rotation measurements on a thin disklike crystal with the field perpendicular to (N-perpendicular to = 0.87) and in the plane (N-parallel to = 0.08) of the disk. By analyzing the mu SR signal we find that the volume fraction of the normal domains grows quasilinearly with applied field at the expense of the Meissner domain fraction. This then provides solid evidence for the intermediate state and type-I superconductivity in the bulk of PdTe2.