I have been reading a lot about quantum computation by using topological materials and I could see that the standard approach is to engineer a p-wave superconductor by using a 1-D semiconductor wire with strong spin orbit coupling combined with a s-wave superconductor as well as a magnetic field. By adjusting the different ingredients properly, a topological phase transition takes place in the system and as a result you get Majorana Zero Modes (MZM) at the ends of the wire.
However, I have noticed that there ir another possibility for coming up with MZM that consists of combining a pure topological insulator such as Bi2Se3, or Bi2Te3 with a superconductor so you end up with a topological superconductor.
I do not understand the advantage or disadvantages of one process over the other, I mean, is there any fundamental difference why we should prefer the second route over the first one? Is a magnetic field necesary in the second route?