Electron-infrared phonon coupling in ABC trilayer graphene

TL;DR

This study reveals that ABC-stacked trilayer graphene exhibits significantly stronger electron-infrared phonon coupling than ABA stacking, providing insights into its unique physical properties and enabling nondestructive stacking order imaging.

Contribution

It demonstrates the stacking order dependence of electron-phonon coupling in trilayer graphene using advanced spectroscopy techniques.

Findings

ABC stacking shows stronger electron-infrared phonon coupling than ABA

Raman and near-field infrared spectroscopy reveal stacking-dependent properties

Insights into superconductivity related to stacking order

Abstract

Stacking order plays a crucial role in determining the crystal symmetry and has significant impacts on electronic, optical, magnetic, and topological properties. Electron-phonon coupling, which is central to a wide range of intriguing quantum phenomena, is expected to be intricately connected with stacking order. Understanding the stacking order-dependent electron-phonon coupling is essential for understanding peculiar physical phenomena associated with electron-phonon coupling, such as superconductivity and charge density waves. In this study, we investigate the effect of stacking order on electron-infrared phonon coupling in graphene trilayers. By using gate-tunable Raman spectroscopy and excitation frequency-dependent near-field infrared nanoscopy, we show that rhombohedral ABC-stacked trilayer graphene has a significantly stronger electron-infrared phonon coupling strength than the Bernal ABA-stacked trilayer graphene. Our findings provide novel insights into the superconductivity and other fundamental physical properties of rhombohedral ABC-stacked trilayer graphene, and can enable nondestructive and high-throughput imaging of trilayer graphene stacking order using Raman scattering.