Angular momentum of vortex-core Majorana zero modes

We recently published a paper reporting that vortex-core Majorana zero modes (MZMs) can carry a nontrivial angular momentum.
We study a modified Fu-Kane model, with a d+id superconducting order parameter on top of a strong topological insulator. We found non-trivial spin and angular-momentum textures, resulting in the emergence of four “flavors” of Majorana zero modes (MZMs).
We classify the MZMs states with respect to the windings of the order parameter and the underlying normal state, beyond the Chern-based classification.
We also assess the stability and topological protection of these MZMs, as well as possible experimental signatures.
Our work provides a new path towards the study and engineering of MZMs for quantum computation.