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 μ₀H_c=13.6 mT. Since type-I superconductivity is unexpected for binary compounds, we have conducted muon spin rotation (μSR) 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_⊥= 0.87) and in the plane (N_|| = 0.08) of the disk. By analyzing the μSR 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.