Correlation of optical conductivity and pairing states in superconducting Weyl semimetals

There are two different pairing potentials for the superconductivity of doped Weyl semimetals, i.e., the internode BCS pairing and the intranode Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing. We show that the superconducting pairing potentials can be clearly distinguished from the frequency characteristics of optical conductivity. The pairing-dependent optical conductivities for the BCS and FFLO pairings are calculated. The optical conductivities exhibit two types of distinct resonances, the Van Hove resonance for the BCS pairing and the resonance with a threshold for FFLO pairing. The result provides a method of identifying the pairing potential in superconducting Weyl semimetals.