  Weyl nodal loop semimetals (WNLs) host a closed nodal line loop Fermi surface
in the bulk, protected zero-energy flat band, or drumhead, surface states, and
strong spin-polarization. The large density of states of the drumhead states
makes WNL semimetals exceedingly prone to electronic ordering. At the same
time, the spin-polarization naively prevents conventional superconductivity due
to its spin-singlet nature. Here we show the complete opposite: WNLs are
extremely promising materials for superconducting Josephson junctions, entirely
due to odd-frequency superconductivity. By sandwiching a WNL between two
conventional superconductors we theoretically demonstrate the presence of very
large Josephson currents, even up to orders of magnitude larger than for normal
metals. The large currents are generated both by an efficient transformation of
spin-singlet pairs into odd-frequency spin-triplet pairing by the Weyl
dispersion and the drumhead states ensuring exceptionally proximity effect. As
a result, WNL Josephson junctions offer unique possibilities for detecting and
exploring odd-frequency superconductivity.
