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arXiv · 2311.02528

Quasi-free-standing AA-stacked bilayer graphene induced by calcium intercalation of the graphene-silicon carbide interface

Antonija Grubišić-Čabo·Jimmy C. Kotsakidis·Yuefeng Yin·Anton Tadich·Matthew Haldon·Sean Solari·John Riley·Eric Huwald·Kevin M. Daniels·Rachael L. Myers-Ward·Mark T. Edmonds·Nikhil Medhekar·D. Kurt Gaskill·Michael S. Fuhrer
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Abstract

We study quasi-freestanding bilayer graphene on silicon carbide intercalated by calcium. The intercalation, and subsequent changes to the system, were investigated by low-energy electron diffraction, angle-resolved photoemission spectroscopy (ARPES) and density-functional theory (DFT). Calcium is found to intercalate only at the graphene-SiC interface, completely displacing the hydrogen terminating SiC. As a consequence, the system becomes highly n-doped. Comparison to DFT calculations shows that the band dispersion, as determined by ARPES, deviates from the band structure expected for Bernal-stacked bilayer graphene. Instead, the electronic structure closely matches AA-stacked bilayer graphene on Ca-terminated SiC, indicating a spontaneous transition from AB- to AA-stacked bilayer graphene following calcium intercalation of the underlying graphene-SiC interface.

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Antonija Grubišić-Čabo, Jimmy C. Kotsakidis, Yuefeng Yin, Anton Tadich, Matthew Haldon, Sean Solari, John Riley, Eric Huwald, Kevin M. Daniels, Rachael L. Myers-Ward, Mark T. Edmonds, Nikhil Medhekar, D. Kurt Gaskill, Michael S. Fuhrer. 2023-11-05. Quasi-free-standing AA-stacked bilayer graphene induced by calcium intercalation of the graphene-silicon carbide interface. https://doi.org/10.3389/fnano.2023.1333127

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