We theoretically predict proximity-induced odd-frequency $\left(\mathrm{odd}-\omega \right)$ pairing on the surface of a Weyl nodal loop semimetal, characterized by a nodal loop Fermi surface and drumheadlike surface states (DSSs), attached to conventional spin-singlet $s$-wave superconducting leads. Due to the complete spin polarization of the DSS, only $\mathrm{odd}-\omega$ equal-spin triplet pairing is present, and we show that it gives rise to a finite Josephson current. Placing an additional ferromagnet in the junction can also generate $\mathrm{odd}-\omega$ mixed-spin triplet pairing, but the pairing and current are not affected if the magnetization is orthogonal to the DSS spin polarization, which further confirms the equal-spin structure of the pairing.

• Received 6 February 2019
• Revised 20 June 2019

DOI:https://doi.org/10.1103/PhysRevB.100.104511