Covalent bonded bilayers from germanene and stanene with topological giant capacitance effects
The discovery of twisted bilayer graphene with tunable superconductivity has diverted great focus at the world of twisted van der Waals heterostructures. Here we propose a paradigm for bilayer materials, where covalent bonding replaces the van der Waals interaction between the layers. On the example of germanene-stanene bilayer, we show that such systems demonstrate fascinating topological properties and manifest giant capacitance effects of the order of C = 102μ F as well as dipole-like charge densities of q = 1 − 2 × 10−4μ C cm−2, showing promise for 2D ferroelectricity. The observed unique behaviour is closely linked to transverse strain-induced buckling deformations at the bilayer/substrate interface. In alternative GeSn bilayer structures with low twist angles the strain distortions trigger rich topological defect physics. We propose that the GeSn bilayer topology may be switched locally by a substrate-strain-induced electric fields. We demonstrate an approach to fabricate covalent bilayer materials, holding vast possibilities to transform applications technologies across solar, energy and optoelectronic sectors.
Funding
EU MSCA-RISE project DiSeTCom (GA 823728)
INFN project TIME2QUEST
985 FSU-2021-030/8474000371
EU H2020 RISE project TERASSE (H2020-823878)
NSFC project No. 11804313
Royal Society, grant number IEC\ R2\202314 and IEC\ R2\202164
History
School
- Science
Department
- Physics
Published in
npj 2D Materials and ApplicationsVolume
7Publisher
Springer NatureVersion
- VoR (Version of Record)
Rights holder
© The AuthorsPublisher statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Acceptance date
2023-03-10Publication date
2023-04-03Copyright date
2023eISSN
2397-7132Publisher version
Language
- en