Moiré-modulated band gap and van Hove singularities in twisted bilayer germanene
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arXiv
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| Autori principali: | , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866913890495889408 |
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| author | Bampoulis, Pantelis Castenmiller, Carolien Klaassen, Dennis J. Mil, Jelle v. de Boeij, Paul L. Ezawa, Motohiko Zandvliet, Harold J. W. |
| author_facet | Bampoulis, Pantelis Castenmiller, Carolien Klaassen, Dennis J. Mil, Jelle v. de Boeij, Paul L. Ezawa, Motohiko Zandvliet, Harold J. W. |
| contents | Twisting bilayers of two-dimensional topological insulators has the potential to create unique quantum states of matter. Here, we successfully synthesized a twisted bilayer of germanene on Ge2Pt(101) with a 21.8$^o$ degrees twist angle, corresponding to a commensurate ($\sqrt{7} \times \sqrt{7}$) structure. Using scanning tunneling microscopy and spectroscopy, we unraveled the structural and electronic properties of this configuration, revealing a moiré-modulated band gap and a well-defined edge state. This band gap opens at AB/BA stacked sites and closes at AA stacked sites, a phenomenon attributed to the electric field induced by the scanning tunneling microscopy tip. Our study further revealed two van Hove singularities at -0.8 eV and +1.04 eV, resulting in a Fermi velocity of $(8 \pm 1) \times 10^5$ m/s. Our tight-binding results uncover a unique quantum state, where the topological properties could be regulated through an electric field, potentially triggering two topological phase transitions. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_14560 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Moiré-modulated band gap and van Hove singularities in twisted bilayer germanene Bampoulis, Pantelis Castenmiller, Carolien Klaassen, Dennis J. Mil, Jelle v. de Boeij, Paul L. Ezawa, Motohiko Zandvliet, Harold J. W. Mesoscale and Nanoscale Physics Twisting bilayers of two-dimensional topological insulators has the potential to create unique quantum states of matter. Here, we successfully synthesized a twisted bilayer of germanene on Ge2Pt(101) with a 21.8$^o$ degrees twist angle, corresponding to a commensurate ($\sqrt{7} \times \sqrt{7}$) structure. Using scanning tunneling microscopy and spectroscopy, we unraveled the structural and electronic properties of this configuration, revealing a moiré-modulated band gap and a well-defined edge state. This band gap opens at AB/BA stacked sites and closes at AA stacked sites, a phenomenon attributed to the electric field induced by the scanning tunneling microscopy tip. Our study further revealed two van Hove singularities at -0.8 eV and +1.04 eV, resulting in a Fermi velocity of $(8 \pm 1) \times 10^5$ m/s. Our tight-binding results uncover a unique quantum state, where the topological properties could be regulated through an electric field, potentially triggering two topological phase transitions. |
| title | Moiré-modulated band gap and van Hove singularities in twisted bilayer germanene |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2403.14560 |