Realization of a one-dimensional topological insulator in ultrathin germanene nanoribbons

Realizing a one-dimensional (1D) topological insulator and identifying the lower-dimensional limit of two-dimensional (2D) behavior are crucial steps toward developing high-density quantum state networks, advancing topological quantum computing, and exploring dimensionality effects in topological materials. Although 2D topological insulators have been experimentally realized, their lower dimensional limit and 1D counterparts remain elusive. Here, we fabricated and characterized arrays of zigzag-terminated germanene nanoribbons, a 2D topological insulator with a large topological bulk gap. The electronic properties of these nanoribbons strongly depend on their width, with topological edge states persisting down to a critical width (∼2 nm), defining the limit of 2D topology. Below this threshold, contrary to the tenfold way classification, we observe zero-dimensional (0D) states localized at the ends of the ultrathin nanoribbons. These end states, topologically protected by time-reversal and mirror symmetries, indicate the realization of a 1D topological insulator with strong spin-orbit coupling. Our findings establish germanene nanoribbons as a platform for investigating 1D topology and dimensionality effects in topological materials.

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Publication Details

Journal
Nature Communications
Published
2025-02-28
DOI
https://doi.org/10.1038/s41467-025-57147-4
Citations
20
Primary Topic
Topological Materials and Phenomena
Type
article
Field-Weighted Citation Impact
24.94

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article

Realization of a one-dimensional topological insulator in ultrathin germanene nanoribbons

Pantelis Bampoulis, Carolien Castenmiller, Dennis J. Klaassen, C. Morais Smith et al.
20 citations
Nature Communications
Topological Materials and Phenomena
24.94
article

Realization of a one-dimensional topological insulator in ultrathin germanene nanoribbons

Pantelis Bampoulis, Carolien Castenmiller, Dennis J. Klaassen, C. Morais Smith, Arie van Houselt, P. L. de Boeij, Harold J. W. Zandvliet, Motohiko Ezawa, Lumen Eek, А. Н. Руденко, Zhiguo Zhang, Esra D. van ’t Westende
article en
20 citations

Abstract

Realizing a one-dimensional (1D) topological insulator and identifying the lower-dimensional limit of two-dimensional (2D) behavior are crucial steps toward developing high-density quantum state networks, advancing topological quantum computing, and exploring dimensionality effects in topological materials. Although 2D topological insulators have been experimentally realized, their lower dimensional limit and 1D counterparts remain elusive. Here, we fabricated and characterized arrays of zigzag-terminated germanene nanoribbons, a 2D topological insulator with a large topological bulk gap. The electronic properties of these nanoribbons strongly depend on their width, with topological edge states persisting down to a critical width (∼2 nm), defining the limit of 2D topology. Below this threshold, contrary to the tenfold way classification, we observe zero-dimensional (0D) states localized at the ends of the ultrathin nanoribbons. These end states, topologically protected by time-reversal and mirror symmetries, indicate the realization of a 1D topological insulator with strong spin-orbit coupling. Our findings establish germanene nanoribbons as a platform for investigating 1D topology and dimensionality effects in topological materials.

Nature CommunicationsVol. 16(1)
Radboud University Nijmegen (NL), Utrecht University (NL), Fudan University (CN), Instituto de Física Teórica (ES), The University of Tokyo (JP), University of Twente (NL)
European Commission, Ministry of Education, Culture, Sports, Science and Technology, Universiteit Utrecht, University of Twente, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, China Scholarship Council, HORIZON EUROPE Framework Programme, Japan Society for the Promotion of Science, Core Research for Evolutional Science and Technology
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Openalex Percentile: Top 0%
Topological Materials and Phenomena
24.94
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