Electronic properties of InAs/Al/EuS hybrid nanowires: Effective Zeeman spin splitting and topological phase diagram*

Motivated by recent experiments on InAs/Al/EuS heterostructures, we theoretically study the electronic properties of semiconductor-superconductor-ferromagnetic insulator hybrid nanowires. Our focus is on the physical mechanisms for inducing the effective Zeeman energy and on whether topological superconductivity can be achieved in these devices. We show that the magnetic proximity effects at the Al/EuS as well as the InAs/EuS interfaces are both essential for inducing a sufficiently large total Zeeman energy. Such a Zeeman energy would also depend on the applied gate voltages, the effect of which is included via an electrostatic potential calculated by the Thomas Fermi-Poisson method. Finally we map out the topological phase diagram of the hybrid system as a function of both the gate voltages and the proximity-induced exchange coupling.