Interacting topological bound states and Majorana fermions in strained nodal superconductors

Landau levels (LL) have been predicted to emerge in systems with Dirac nodal points under applied nonuniform strain. We consider two-dimensional (2D), d(xy) singlet (2D-S), and three-dimensional (3D) p(x) +/- ip(y) equal-spin triplet (3D-T) superconductors. We demonstrate the topological bound state and spinful Majorana nature of the bulk gapless zeroth LLs in the singlet and triplet cases, respectively. Strain along certain directions can induce two topologically distinct phases in the bulk, with zeroth LLs localized at the interface. These modes are unstable toward ferromagnetism for 2D-S cases. True Majorana fermions in 3D-T allow for more exotic possibilities.