Kramer’s degenerate magnetism and superconductivity: Part I: General Theory

The interplay of superconductivity with translation invariant - Kramer’s degenerate-magnetic states, such as loop currents or odd-parity multipole magnetic order is examined. This work is motivated by the recent likely observation of the coexistence between an odd-parity multipole magnetic state and superconductivity in CeRh₂As₂ as well as studies of the interplay of loop currents with superconductivity in the cuprates. We show that the presence of such magnetic states generically suppress superconductivity, whether it be spin-singlet or spin-triplet. The superconducting states also often give rise to Bogoliubov Fermi surfaces. Despite the general suppression of superconductivity, we show that superconductivity can survive in two cases: a) by inducing finite momentum pairing states b) or under suitable symmetry conditions.