Engineering topological materials—one layer of atoms
at a time
Matthew Brahlek, Materials Institute, Penn. State University.
The
unusual, Dirac-like electronic states that emerge on the surface of topological
insulator (TIs) are of wide interest for both fundamental studies as well as a range
of practical applications. Despite the theoretical beauty, defects in real
materials mask these interesting properties. Here, I will focus on how the
atomic-scale control of molecular beam epitaxy, which is the gold-standard for
synthesizing the highest quality materials, opens up pathways to control defects
thus enabling the exploration of the intrinsic properties in TIs. In particular,
I will discuss the limits from the ultra-clean, where the surface-states can be
either coupled or decoupled, to the highly-disordered, where the notion of
topological character breaks down.