An application of a generalized Anderson theorem*

We present a general theoretical framework for analyzing irradiation studies in spin-orbit-coupled multiorbital systems, which is based on a generalized Anderson theorem for multiband superconductors. We apply this framework to interpret results from a theory-experiment collaboration about the impact of nonmagnetic disorder on the normal and superconducting properties of the type-II Dirac semimetal PdTe₂. Experimental measurements of longitudinal and Hall resistivity, thermal conductivity and London penetration depth using the tunnel-diode resonator technique are performed for various irradiation doses. They yield that the superconducting transition temperature is suppressed at a rate about 16 times lower than described by the Abrikosov-Gor’kov law. This imposes quantitative constraints on the gap anisotropies for each of the possible pairing candidate states. We conclude that the most likely pairing candidate is an unconventional A⁺⁻_1g state, since other candidates require additional assumptions about the orbital structure of the disorder potential to be consistent with our experimental results.