2026/05/31 by Kyoung-Min Kim, Gibaik Sim, Moon Jip Park
Physics and Astronomy · #cond-mat.str-el #cond-mat.mes-hall #cond-mat.supr-con
8+12 pages
arxiv created 2026/08/05 · arxiv updated 2026/08/06
Fermi-surface spin splitting generated by non-relativistic exchange fields provides a new route to topological superconductivity without relying on strong spin-orbit coupling. Here, we study superconducting instabilities of a square-lattice p-wave magnet with onsite and nearest-neighbour attractive interactions. The odd-parity exchange field removes inversion symmetry in the spin-split electronic structure, mixing singlet and triplet order parameters within a single symmetry channel. The leading instability is a mixed-parity A1 Ising state, in which singlet components coexist with the px-wave triplet component, whose d-vector is locked along the exchange-field axis. As the nearest-neighbour attraction grows, this Ising state undergoes a transition into a nodal topological superconducting phase with Majorana edge modes protected by momentum-resolved winding numbers. These modes extend over finite momentum intervals bounded by the surface projections of bulk point nodes. We further show that a Zeeman field perpendicular to the exchange field can induce a ℤ2 topological superconducting phase. Our results identify p-wave magnets as a versatile testbed for topological superconductivity driven by non-relativistic spin splitting.