Symmetry-Protected Topological Superconductivity in Magnetic Metals

We show that topological superconductivity can be generally induced in a magnetic metal through the superconducting proximity effect. In this case, the topological superconductivity originates from band degeneracies controlled by crystalline symmetries. We demonstrate this general scheme in a model with a 4-fold band degeneracy protected by the space group P4=nmm. We show that first order or second-order topological superconductivity can be realized in the presence of a ferromagnetic order or an antiferromagnetic order respectively. We derive the corresponding topological invariants and analyze Majorana modes. Our study provides a general method to realize topological superconductivity and help to identify new platforms to generate Majorana zero modes.