In the Focus of Research Unit: Strain and Charge Density Wave in Epitaxial Graphene
DFG-Research Unit at Chemnitz University of Technology studied the proximity coupling in Sn-intercalated epitaxial graphene, published in „Carbon“
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Dr. Narmina Balayeva and Dr. Zamin Mamiyev are measuring the structural properties of two-dimensional tin layers through electron diffraction at the Institute of Physics. Photo: James Oyuga
The Research Unit “Proximity-Induced Correlation Effects in Low-Dimensional Structures” under the leadership of Chemnitz University of Technology is at the forefront of exploring the epitaxial growth and interface engineering of two-dimensional heterostructures. Current efforts are directed towards intercalating heavy carbon group elements beneath epitaxial graphene to fine-tune its properties and simultaneously create novel two-dimensional electron gas systems in close proximity.
In a recent study published in the renowned journal "Carbon", the research team from the Chairs of Semiconductor Physics and Solid Surface Analytics at Chemnitz University of Technology unveiled groundbreaking insights into hybrid two-dimensional systems involving intercalated tin and epitaxial graphene. Using advanced techniques such as low-energy electron diffraction, scanning tunneling microscopy, and Raman spectroscopy, the researchers found that tin nanostructures intercalated beneath graphene induce strain and Kekulé-type charge density waves in graphene through strong proximity interactions. This breakthrough enhances graphene's potential for applications in valleytronics and spintronics while deepening our understanding of structural and electronic coupling in two-dimensional systems.
Tin stands out among elements for its ability to form diverse phases from correlated Mott insulators to metallic layers, each uniquely influencing graphene. “The targeted formation of specific tin interfaces and their structural and electronic characterization have revealed how the interaction of graphene with proximitized quantum systems can be finely tuned,” says Dr. Zamin Mamiyev, who coordinated the experiments.
The ultimate electronic properties of graphene are highly related to its phonon dynamics — the vibrational properties of the crystal lattice. “Our study demonstrated that different phases of tin-induced interface layers can modulate charge carrier concentration and lattice dynamics of graphene in a controlled manner," explains Dr. Narmina Balayeva, a postdoctoral researcher at the Professorship of Semiconductor Physics.
Since the experimental realization of graphene as an atomically thin, stable two-dimensional material, scientists worldwide have sought to develop similar quantum systems with versatile properties. “Recent advancements in two-dimensional materials have introduced the concept of confined epitaxy, where new atomically thin structures are grown directly at interfaces. As we showed in our study, this approach not only leverages their inherent stability but also enables the direct study of interfacial coupling of different electronic systems,” explains Prof. Dr. Christoph Tegenkamp, head of the Professorship of Analytics on Solid Surfaces at Chemnitz University of Technology and spokesperson for the DFG research group.
In the future, researchers aim to explore additional intercalation phases using similar experimental techniques, further advancing the foundation for novel quantum materials and their potential applications.
Publikation: Confinement induced strain effects in epitaxial graphene; Zamin Mamiyev, Narmina O. Balayeva, Chitran Ghosal, Dietrich R.T. Zahn, Christoph Tegenkamp; Carbon
DOI: https://doi.org/10.1016/j.carbon.2025.120002
For further information please contact Prof. Dr. Christoph Tegenkamp, Telefon 0371 531-33103, E-Mail christoph.tegenkamp@physik.tu-chemnitz.de.
(Author and Translation: Zamin Mamiyev)
Mario Steinebach
30.01.2025
