Electronic structure of amorphous topological and magnetic materials

The discovery of three-dimensional topological insulators (TIs) ushered in a new era of considering the geometry of the many-electron wavefunction in determining materials' novel behaviors, and fostered identification of subsequent phenomena in TIs reliant on their unique surface band structure. Recently, the characteristic electronic features of TIs were reported in amorphous Bi2Se3 films, including a semiconducting bulk and spin-momentum-locked bands with surface-like character. This result showed that amorphous systems support states traditionally described only via momentum-space analysis, which broadened the theoretical understanding of these states. We will report on recent progress in uncovering the unique chemical and electronic signatures of amorphous topological and magnetic materials using a range of photoemission spectroscopies.