TY  - JOUR
AU  - Leis, Arthur
AU  - Schleenvoigt, Michael
AU  - Cherepanov, Vasily
AU  - Lüpke, Felix
AU  - Schüffelgen, Peter
AU  - Mussler, Gregor
AU  - Grützmacher, Detlev
AU  - Voigtländer, Bert
AU  - Tautz, F. Stefan
TI  - Lifting the Spin‐Momentum Locking in Ultra‐Thin Topological Insulator Films
JO  - Advanced quantum technologies
VL  - 4
IS  - 11
SN  - 2511-9044
CY  - Weinheim
PB  - Wiley-VCH Verlag
M1  - FZJ-2021-03711
SP  - 2100083 -
PY  - 2021
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000695620900001
DO  - DOI:10.1002/qute.202100083
UR  - https://juser.fz-juelich.de/record/897249
ER  -