Journal Article

FZJ-2021-03711

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Lifting the Spin‐Momentum Locking in Ultra‐Thin Topological Insulator Films

Leis, A. (Corresponding author)FZJ* ; Schleenvoigt, M.FZJ* ; Cherepanov, V.FZJ* ; Lüpke, F.FZJ* ; Schüffelgen, P.FZJ* ; Mussler, G.FZJ* ; Grützmacher, D.FZJ* ; Voigtländer, B.FZJ* ; Tautz, F. S.FZJ*

2021
Wiley-VCH Verlag Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/31298  doi:10.1002/qute.202100083

Abstract: 3D topological insulators are known to carry 2D Dirac-like topological surface states in which spin-momentum locking prohibits backscattering. When thinned down to a few nanometers, the hybridization between the topological surface states at the top and bottom surfaces results in a topological quantum phase transition, which can lead to the emergence of a quantum spin Hall phase. Here, the thickness-dependent transport properties across the quantum phase transition are studied on the example of (Bi0.16Sb0.84.)2Te3 films, with a four-tip scanning tunneling microscope. The findings reveal an exponential drop of the conductivity below the critical thickness. The steepness of this drop indicates the presence of spin-conserving backscattering between the top and bottom surface states, effectively lifting the spin-momentum locking and resulting in the opening of a gap at the Dirac point. The experiments provide a crucial step toward the detection of quantum spin Hall states in transport measurements.

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Contributing Institute(s):

1. Quantum Nanoscience (PGI-3)

Research Program(s):

1. 5213 - Quantum Nanoscience (POF4-521) (POF4-521)
2. DFG project 443416235 - 1D topologische Supraleitung und Majorana Zustände in van der Waals Heterostrukturen charakterisiert durch Rastersondenmikroskopie (443416235)

Appears in the scientific report 2021

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Database coverage:
; ; Clarivate Analytics Master Journal List ; DEAL Wiley ; Emerging Sources Citation Index ; NCBI Molecular Biology Database ; Web of Science Core Collection

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