Fractional magnetoresistance oscillations in spin-triplet superconducting rings

Despite many candidates for spin-triplet superconductivity so far, no definitive evidence has been produced. This study proposes a signature, related to the flux quantisation, that could be used to identify spin-triplet superconductors in mesoscopic rings via the magnetoresistance oscillations. Half-quantum vortices in spin-triplet superconductors are predicted to host Majorana zero modes and may provide a viable platform for topological quantum computation. Recent works also suggested that, in thin mesoscopic rings, the superconducting pairing symmetry can be probed via Little-Parks-like magnetoresistance oscillations of periodicity phi(0) = h/2e that persist below the critical temperature. Here we use the London limit of Ginzburg-Landau theory to study these magnetoresistance oscillations resulting from thermal vortex tunneling in spin-triplet superconducting rings. For a range of temperatures in the presence of disorder, we find magnetoresistance oscillations with an emergent fractional periodicity phi(0)/n, where the integer n >= 3 is entirely determined by the ratio of the spin and charge superfluid densities. These fractional oscillations can unambiguously confirm the spin-triplet nature of superconductivity and directly reveal the tunneling of half-quantum vortices in real-world candidate materials.