Lifting the spin-momentum locking in ultra-thin topological insulator films
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arXiv
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| Autores principales: | , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2021
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| _version_ | 1866929226816421888 |
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| author | Leis, Arthur Schleenvoigt, Michael Cherepanov, Vasily Lüpke, Felix Schüffelgen, Peter Mussler, Gregor Grützmacher, Detlev Voigtländer, Bert Tautz, F. Stefan |
| author_facet | Leis, Arthur Schleenvoigt, Michael Cherepanov, Vasily Lüpke, Felix Schüffelgen, Peter Mussler, Gregor Grützmacher, Detlev Voigtländer, Bert Tautz, F. Stefan |
| contents | Three-dimensional (3D) topological insulators (TIs) 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, we study the thickness-dependent transport properties across the quantum phase transition on the example of (Bi$_{0.16}$Sb$_{0.84}$)$_2$Te$_3$ films, with a four-tip scanning tunnelling microscope. Our 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. Our experiments provide crucial steps towards the detection of quantum spin Hall states in transport measurements. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2106_06217 |
| institution | arXiv |
| publishDate | 2021 |
| record_format | arxiv |
| spellingShingle | Lifting the spin-momentum locking in ultra-thin topological insulator films Leis, Arthur Schleenvoigt, Michael Cherepanov, Vasily Lüpke, Felix Schüffelgen, Peter Mussler, Gregor Grützmacher, Detlev Voigtländer, Bert Tautz, F. Stefan Mesoscale and Nanoscale Physics Three-dimensional (3D) topological insulators (TIs) 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, we study the thickness-dependent transport properties across the quantum phase transition on the example of (Bi$_{0.16}$Sb$_{0.84}$)$_2$Te$_3$ films, with a four-tip scanning tunnelling microscope. Our 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. Our experiments provide crucial steps towards the detection of quantum spin Hall states in transport measurements. |
| title | Lifting the spin-momentum locking in ultra-thin topological insulator films |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2106.06217 |