Spin texture in weak topological insulators: the role of bulk states and band bending

2020/06/18 by F. Rost, R.S. Gupta, Rost, F. +7
Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Topological Materials and Phenomena

paper · pdf · doi:10.48550/arxiv.2006.10395

openalex publication_date 2020/06/18 · openalex created_date 2020/06/25 · openalex updated_date 2026/07/28

Abstract

We derive the spin texture of a weak topological insulator via a supersymmetric approach that includes the roles of the bulk gap edge states and surface band bending. We find the spin texture can take one of four forms: (i) helical, (ii) hyperbolic, (iii) hedgehog, with spins normal to the Dirac-Weyl cone of the surface state, and (iv) hyperbolic hedgehog. Band bending determines the winding number in the case of a helical texture, and for all textures can be used to tune the spin texture polarization to zero. For the weak topological insulator SnTe, we show that inclusion of band bending is crucial to obtain the correct texture winding number for the (111) surface facet Γ-point Dirac-Weyl cone. We argue that hedgehogs will be found only in low symmetry situations.

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