Interface symmetry and non-helical states in topological insulator-based heterostructures

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Interface symmetry and non-helical states...
2019. 06. 17. 14:00
Building F, Entrance III, seminar room of Department of Theoretical Physics
Ilya Vekhter (LSU)

Incorporating topological insulators (TIs) into prototype devices requires creating interfaces between topological and non-topological materials. It is often assumes that the interface states have the same properties as the well-studied helical Dirac states at the surfaces of TIs. I consider a planar boundary between a topologically-trivial semiconductor and a TI, and show that the topological interface states may be qualitatively different from those at the vacuum surface, are controlled by the residual symmetry of the interface,  and may exhibit elliptical contours of constant energy and complex spin textures with broken helicity. I will also discuss experimental signatures of broken symmetry of these states and propose measurements for its detection.