Abstract

In this work I explore the requirements for harboring Majorana fermions in epitaxial InAs-Al nanowire hybrids. The main focus is on the interplay of the orbital and Zeeman magnetic field effects and the concomitant impact on the topological phase diagram. In fact, I present new hybrid devices in which orbital effects are enhanced and play an important role for realizing the topological phase transition. In addition, I discuss alternative Majorana devices that do not require the application of an external magnetic field, as for instance, InAs-Al hybrids in proximity to ferromagnetic insulators such as EuS. For carrying out the theoretical analysis I consider a microscopic model Hamiltonian restricted to the three energetically lowest confinement channels and include both Dresselhaus and Rashba types of spin-orbit interaction.