Intercalant-induced Kekule ordering and gap opening in quasi-free-standing graphene

Fuente: arXiv
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Main Authors: Ngo, Huu Thoai, Mamiyev, Zamin, Witt, Niklas, Wehling, Tim, Tegenkamp, Christoph
Format: Preprint
Published: 2025
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author Ngo, Huu Thoai
Mamiyev, Zamin
Witt, Niklas
Wehling, Tim
Tegenkamp, Christoph
author_facet Ngo, Huu Thoai
Mamiyev, Zamin
Witt, Niklas
Wehling, Tim
Tegenkamp, Christoph
contents We present a comprehensive investigation of the structural and electronic properties of Sn intercalated buffer layers on SiC(0001) using low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/STS), spot-profile analysis low-energy electron diffraction (SPA-LEED), and density functional theory (DFT) calculations. Sn intercalation effectively decouples the buffer layer, yielding quasi-free-standing monolayer graphene (QFMLG) while introducing local lattice distortions. Bias-dependent STM imaging revealed the coexistence of conventional and Kekule-ordered graphene domains, governed by the underlying Sn(1x1) reconstruction at the SiC interface. The measured STS spectra exhibit good agreement with DFT results. However, achieving homogeneous Sn(1x1) domains remains challenging, apparently, due to strain within the Sn monolayer, which drives the emergence of Kekule distortions and the associated electronic band-gap opening omogeneously in graphene. These findings highlight the crucial role of intercalant homogeneity and strain in tuning graphene`s structural and electronic properties.
format Preprint
id arxiv_https___arxiv_org_abs_2512_20366
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Intercalant-induced Kekule ordering and gap opening in quasi-free-standing graphene
Ngo, Huu Thoai
Mamiyev, Zamin
Witt, Niklas
Wehling, Tim
Tegenkamp, Christoph
Mesoscale and Nanoscale Physics
Materials Science
We present a comprehensive investigation of the structural and electronic properties of Sn intercalated buffer layers on SiC(0001) using low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/STS), spot-profile analysis low-energy electron diffraction (SPA-LEED), and density functional theory (DFT) calculations. Sn intercalation effectively decouples the buffer layer, yielding quasi-free-standing monolayer graphene (QFMLG) while introducing local lattice distortions. Bias-dependent STM imaging revealed the coexistence of conventional and Kekule-ordered graphene domains, governed by the underlying Sn(1x1) reconstruction at the SiC interface. The measured STS spectra exhibit good agreement with DFT results. However, achieving homogeneous Sn(1x1) domains remains challenging, apparently, due to strain within the Sn monolayer, which drives the emergence of Kekule distortions and the associated electronic band-gap opening omogeneously in graphene. These findings highlight the crucial role of intercalant homogeneity and strain in tuning graphene`s structural and electronic properties.
title Intercalant-induced Kekule ordering and gap opening in quasi-free-standing graphene
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2512.20366