Magnetic Oscillation of Optical Phonon in ABA- and ABC-Stacked Trilayer Graphene

TL;DR

This study compares magneto-Raman scattering of optical phonons in ABA- and ABC-stacked trilayer graphene, revealing stacking-dependent differences in phonon oscillations and electronic coupling, which can help identify stacking order and electronic structure.

Contribution

It provides the first comparative analysis of magnetophonon oscillations in ABA- and ABC-stacked trilayer graphene, highlighting the influence of stacking order on optical and electronic properties.

Findings

ABA-stacked TLG shows magnetophonon oscillations consistent with bilayer doublets.

ABC-stacked TLG exhibits suppressed oscillations up to 9 T due to enhanced band chirality.

Stacking order significantly affects electron-phonon coupling and Landau level transitions.

Abstract

We present a comparative measurement of the G-peak oscillations of phonon frequency, Raman intensity and linewidth in the Magneto-Raman scattering of optical E2g phonons in mechanically exfoliated ABA- and ABC-stacked trilayer graphene (TLG). Whereas in ABA-stacked TLG, we observe magnetophonon oscillations consistent with single-bilayer chiral band doublets, the features are flat for ABC-stacked TLG up to magnetic fields of 9 T. This suppression can be attributed to the enhancement of band chirality that compactifies the spectrum of Landau levels and modifies the magnetophonon resonance properties. The drastically different coupling behaviour between the electronic excitations and the E2g phonons in ABA- and ABC-stacked TLG reflects their different electronic band structures and the electronic Landau level transitions and thus can be another way to determine the stacking orders and to probe the stacking-order-dependent electronic structures. In addition, the sensitivity of the magneto-Raman scattering to the particular stacking order in few layers graphene highlights the important role of interlayer coupling in modifying the optical response properties in van der Waals layered materials.