Site-Specific Orbital Symmetry Breaking in Epitaxial Graphene on Silicon Carbide
Abstract
The epitaxial graphene grown on SiC interface has been the subject of tremendous research efforts to control its electronic transport properties in the quest for graphene electronic applications. The electronic structure of the epitaxial graphene buffer layer on SiC(0001) is investigated at the atomic scale using monochromated electron energy loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscope (STEM). The C K-edge reveals spectral fine structures distinctly different from free-standing graphene layer, providing direct experimental evidence of a modified bonding environment. Ab initio calculations providing a site-resolved probe of orbital character to elucidate the origin of these spectral features: covalent bonding between one-quarter of the buffer-layer carbon atoms and the substrate silicon atoms induces partial sp3 hybridization, quenching the out-of-plane π states and disrupting π-conjugation across the interfacial layer. Substrate-imposed symmetry breaking further lifts the in-plane orbital degeneracy. This orbital-engineering framework, rooted in π-state quenching and site-specific symmetry breaking, establishes a quantitative basis for tailoring graphene-substrate interfaces toward next-generation low-energy transistor applications.
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BibTeX
@misc{paidi2026sitespecific,
title = {{Site-Specific Orbital Symmetry Breaking in Epitaxial Graphene on Silicon Carbide}},
author = {Vinod K. Paidi and Yves Joly and Alex Taekyung Lee and Guillaume Radtke and Vlado K. Lazarov and Demie Kepaptsoglou and Quentin M. Ramasse and Matthieu Bugnet},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.04760},
eprint = {2610.04760},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.04760},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Site-Specific Orbital Symmetry Breaking in Epitaxial Graphene on Silicon Carbide
AU - Vinod K. Paidi
AU - Yves Joly
AU - Alex Taekyung Lee
AU - Guillaume Radtke
AU - Vlado K. Lazarov
AU - Demie Kepaptsoglou
AU - Quentin M. Ramasse
AU - Matthieu Bugnet
PY - 2026
DA - 2026/10/03
PB - arXiv
DO - 10.48550/arxiv.2610.04760
UR - https://arxiv.org/abs/2610.04760
AB - The epitaxial graphene grown on SiC interface has been the subject of tremendous research efforts to control its electronic transport properties in the quest for graphene electronic applications. The electronic structure of the epitaxial graphene buffer layer on SiC(0001) is investigated at the atomic scale using monochromated electron energy loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscope (STEM). The C K-edge reveals spectral fine structures distinctly different from free-standing graphene layer, providing direct experimental evidence of a modified bonding environment. Ab initio calculations providing a site-resolved probe of orbital character to elucidate the origin of these spectral features: covalent bonding between one-quarter of the buffer-layer carbon atoms and the substrate silicon atoms induces partial sp^3 hybridization, quenching the out-of-plane π states and disrupting π-conjugation across the interfacial layer. Substrate-imposed symmetry breaking further lifts the in-plane orbital degeneracy. This orbital-engineering framework, rooted in π-state quenching and site-specific symmetry breaking, establishes a quantitative basis for tailoring graphene-substrate interfaces toward next-generation low-energy transistor applications.
ER -