The intense search for topological superconductivity is inspired by the prospect that it hosts Majorana quasiparticles. We explore in this work the optimal design for producing topological superconductivity by combining a quantum Hall state with an ordinary superconductor. To this end, we consider a microscopic model for a topologically trivial two-dimensional p-wave superconductor exposed to a magnetic field and find that the interplay of superconductivity and Landau level physics yields a rich phase diagram of states as a function of μ/t and Δ/t, where μ,t, and Δ are the chemical potential, hopping strength, and the amplitude of the superconducting gap. In addition to quantum Hall states and topologically trivial p-wave superconductor, the phase diagram also accommodates regions of topological superconductivity. Most importantly, we find that application of a nonuniform, periodic magnetic field produced by a square or a hexagonal lattice of h/e fluxoids greatly facilitates regions of topological superconductivity in the limit of Δ/t→0. In contrast, a uniform magnetic field, a hexagonal Abrikosov lattice of h/2e fluxoids, or a one-dimensional lattice of stripes produces topological superconductivity only for sufficiently large Δ/t.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics