Journal Article

FZJ-2022-03024

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Probing Edge State Conductance in Ultra‐Thin Topological Insulator Films

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

2022
Wiley-VCH Verlag Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/31849  doi:10.1002/qute.202200043

Abstract: Quantum spin Hall (QSH) insulators have unique electronic properties, comprising a band gap in their 2D interior and 1D spin-polarized edge states in which current flows ballistically. In scanning tunneling microscopy (STM), the edge states manifest themselves as an enhanced local density of states (LDOS). However, there is a significant research gap between the observation of edge states in nanoscale spectroscopy, and the detection of ballistic transport in edge channels which typically relies on transport experiments with microscale lithographic contacts. Here, few-layer films of the 3D topological insulator (BixSb)2Te3 are studied, for which a topological transition to a 2D topological QSH insulator phase has been proposed. Indeed, an edge state in the LDOS is observed within the band gap. Yet, in nanoscale transport experiments with a four-tip STM, two-quintuple-layer films do not exhibit a ballistic conductance in the edge channels and thus no QSH edge states. This demonstrates that the detection of edge states in spectroscopy can be misleading with regard to the identification of a QSH phase. In contrast, nanoscale multi-tip transport experiments are a robust method for effectively pinpointing ballistic edge channels, as opposed to trivial edge states, in quantum materials.

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Contributing Institute(s):

1. Quantum Nanoscience (PGI-3)
2. Halbleiter-Nanoelektronik (PGI-9)
3. Zentralinstitut für Technologie (ZEA-1)

Research Program(s):

1. 5213 - Quantum Nanoscience (POF4-521) (POF4-521)
2. 5222 - Exploratory Qubits (POF4-522) (POF4-522)
3. DFG project 443416235 - 1D topologische Supraleitung und Majorana Zustände in van der Waals Heterostrukturen charakterisiert durch Rastersondenmikroskopie (443416235)

Appears in the scientific report 2022

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Web of Science Core Collection

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