High density superconductor-semiconductor-superconductor junctions have a small induced superconducting gap due to the quasiparticle trajectories with a large momentum parallel to the junction having a very long flight time.
Andreev bound states in hybrid superconductor-semiconductor devices can have near-zero energy in the topologically trivial regime as long as the confinement potential is sufficiently smooth.
Spin-orbit interaction (SOI), a relativistic effect linking the motion of an electron (orbit) with its magnetic moment (spin), is an essential ingredient for various realisations of topological superconductivity, which host Majorana zero-modes, the building blocks of topological quantum computation.