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Keynote Speaker

Dr. Martin Rejhon

Faculty of Mathematics and Physics, Charles University, Czechia
Exploring ABC-stacked graphene domains in untwisted epitaxial graphene
 
Charles University, Faculty of Mathematics and Physics, Institute of Physics
 

In graphene, emergent properties such as superconductivity to ferroelectricity have been observed in ABC-stacked domains, typically obtained by exfoliation followed by expert mechanical twisting and alignment with the desired orientation, a process very challenging and nonscalable.

Here, we demonstrate that graphene in the ABC stacking domain can be obtained using a scalable growth technique, namely, the thermal decomposition of silicon carbide. Using conductive atomic force microscopy, we identified distinct conductivity patterns in untwisted three-layered epitaxial graphene on silicon carbide. These patterns revealed the presence of ABA and ABC domains, matching the conductivity differences observed in twisted exfoliated graphene and those predicted by density functional theory. The size and geometry of the stacking domains depend on the interplay between strains, solitons crossing, and shape of the three-layer regions. Interestingly, we demonstrate the growth of three-layer regions in which the ABA/ABC stacking domains self-organize in stable stripes of a few tens of nanometers (Fig. 1b). This study demonstrates the potential of the thermal decomposition method for producing ABA/ABC domains, paving the way for future applications in electronic and optoelectronic devices

 

 
 
 

Figure 1: c-AFM images of an epitaxial graphene film with visible stripes in conductivity on a three layer epitaxial graphene.