Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface

Fuente: arXiv
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Autori principali: Tilgner, Niclas, Wolff, Susanne, Soubatch, Serguei, Lee, Tien-Lin, Unigarro, Andres David Peña, Gemming, Sibylle, Tautz, F. Stefan, Kumpf, Christian, Seyller, Thomas, Göhler, Fabian, Schädlich, Philip
Natura: Preprint
Pubblicazione: 2025
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author Tilgner, Niclas
Wolff, Susanne
Soubatch, Serguei
Lee, Tien-Lin
Unigarro, Andres David Peña
Gemming, Sibylle
Tautz, F. Stefan
Kumpf, Christian
Seyller, Thomas
Göhler, Fabian
Schädlich, Philip
author_facet Tilgner, Niclas
Wolff, Susanne
Soubatch, Serguei
Lee, Tien-Lin
Unigarro, Andres David Peña
Gemming, Sibylle
Tautz, F. Stefan
Kumpf, Christian
Seyller, Thomas
Göhler, Fabian
Schädlich, Philip
contents Quantum Spin Hall Insulators (QSHI) have been extensively studied both theoretically and experimentally because they exhibit robust helical edge states driven by spin-orbit coupling and offer the potential for applications in spintronics through dissipationless spin transport. However, to realize devices, it is indispensable to gain control over the interaction of the active layer with the substrate, and to protect it from environmental influences. Here we show that a single layer of elemental Bi, formed by intercalation of an epitaxial graphene buffer layer on SiC(0001), is a promising candidate for a QSHI. This layer can be reversibly switched between an electronically inactive precursor state and a ``bismuthene state'', the latter exhibiting the predicted band structure of a true two-dimensional bismuthene layer. Switching is accomplished by hydrogenation (dehydrogenation) of the sample, i.e., a partial passivation (activation) of dangling bonds of the SiC substrate, causing a lateral shift of Bi atoms involving a change of the adsorption site. In the bismuthene state, the Bi honeycomb layer is a prospective QSHI, inherently protected by the graphene sheet above and the H-passivated substrate below. Thus, our results represent an important step towards protected QSHI systems beyond graphene.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03314
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface
Tilgner, Niclas
Wolff, Susanne
Soubatch, Serguei
Lee, Tien-Lin
Unigarro, Andres David Peña
Gemming, Sibylle
Tautz, F. Stefan
Kumpf, Christian
Seyller, Thomas
Göhler, Fabian
Schädlich, Philip
Mesoscale and Nanoscale Physics
Materials Science
Quantum Spin Hall Insulators (QSHI) have been extensively studied both theoretically and experimentally because they exhibit robust helical edge states driven by spin-orbit coupling and offer the potential for applications in spintronics through dissipationless spin transport. However, to realize devices, it is indispensable to gain control over the interaction of the active layer with the substrate, and to protect it from environmental influences. Here we show that a single layer of elemental Bi, formed by intercalation of an epitaxial graphene buffer layer on SiC(0001), is a promising candidate for a QSHI. This layer can be reversibly switched between an electronically inactive precursor state and a ``bismuthene state'', the latter exhibiting the predicted band structure of a true two-dimensional bismuthene layer. Switching is accomplished by hydrogenation (dehydrogenation) of the sample, i.e., a partial passivation (activation) of dangling bonds of the SiC substrate, causing a lateral shift of Bi atoms involving a change of the adsorption site. In the bismuthene state, the Bi honeycomb layer is a prospective QSHI, inherently protected by the graphene sheet above and the H-passivated substrate below. Thus, our results represent an important step towards protected QSHI systems beyond graphene.
title Reversible Switching of the Environment-Protected Quantum Spin Hall Insulator Bismuthene at the Graphene/SiC Interface
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2502.03314