Abstract
The search for exotic new topological states of matter in widely accessible materials, for which the manufacturing process is mastered, is one of the major challenges of the current topological physics. Here we predict higher order topological insulator state in quantum wells based on the most common semiconducting materials. By successively deriving the bulk and boundary Hamiltonians, we theoretically prove the existence of topological corner states due to cubic symmetry in quantum wells with double band inversion. We show that the appearance of corner states does not depend solely on the crystallographic orientation of the meeting edges, but also on the growth orientation of the quantum well. Our theoretical results significantly extend the application potential of topological quantum wells based on IV, II–VI and III–V semiconductors with diamond or zinc-blende structures.
Highlights
The search for exotic new topological states of matter in widely accessible materials, for which the manufacturing process is mastered, is one of the major challenges of the current topological physics
A large part of the experimental study of 2D higher-order topological insulators (HOTIs) has been performed in engineered metamaterials[24,25,26,27,28,29,30,31,32,33,34], while only a few candidates have been theoretically predicted in solids, including black phosphorene35, graphdiyne36, bismuthene[37] and twisted bilayer graphene at certain a ngles[38]
We have investigated the existence conditions for 0D corner states in cubic semiconductor QWs with double band inversion
Summary
The search for exotic new topological states of matter in widely accessible materials, for which the manufacturing process is mastered, is one of the major challenges of the current topological physics. We predict higher order topological insulator state in quantum wells based on the most common semiconducting materials. HOTIs that fall into the latter case do not host 0D corner states within their bulk band-gap and, as such, cannot be distinguished from trivial insulators by their spectrum alone Even in this case the higher-order topology can be still identified via a fractional corner a nomaly[22,23]. Twisted bilayer graphene can be a realistic candidate to probe 2D HOTI state experimentally, it is still highly desirable to identify controllable and widely accessible higher-order topological materials. Such a list can be obviously extended by including variety of type-II broken-gap QW h eterostructures[45,46,47,48] (similar to the InAs/GaSb QWs) on the basis of III–V semiconductors and their alloys
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