Majorana zero modes in a heterogeneous structure of topological and trivial domains in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>FeSe</mml:mi> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mi>x</m

One of the most puzzling observations in the putative topological superconductor FeSe${}_{1\ensuremath{-}x}$Te${}_{x}$ is that not all vortices possess Majorana zero modes (MZMs). The authors propose here that this phenomenon arises from a heterogeneous mixture of strong topological and trivial superconducting domains, with only vortices in the former exhibiting MZMs. A unique spectroscopic signature separates topological and trivial vortices: a domain wall harboring a Majorana edge mode, which, when a vortex crosses from a trivial to a topological domain, is transferred to the vortex as an MZM.