Observation of Chirality Transition of Quasiparticles at Stacking Solitons in Trilayer Graphene

TL;DR

This study directly observes the smooth transition of quasiparticle chirality at stacking solitons in trilayer graphene, revealing a key link between stacking order and quasiparticle properties through spatially-resolved Landau level spectroscopy.

Contribution

It provides the first direct measurement of quasiparticle chirality transition at stacking domain walls in trilayer graphene using high-field tunneling spectra.

Findings

Quasiparticle chirality transitions smoothly across stacking solitons.

Landau level spectra reveal evolution from l=1&2 to l=3 chirality.

Transition correlates with stacking order change in TLG.

Abstract

Trilayer graphene (TLG) exhibits rich novel electronic properties and extraordinary quantum Hall phenomena owning to enhanced electronic interactions and tunable chirality of its quasiparticles. Here, we report direct observation of chirality transition of quasiparticles at stacking solitons of TLG via spatial-resolved Landau level spectroscopy. The one-dimensional stacking solitons with width of the order of 10 nm separate adjacent Bernal-stacked TLG and rhombohedral-stacked TLG. By using high field tunneling spectra of scanning tunneling microscopy, we measured Landau quantization in both the Bernal-stacked TLG and the rhombohedral-stacked TLG and, importantly, we observed evolution of quasiparticles between the chiral degree l = 1&2 and l = 3 across the stacking domain wall solitons. Our experiment indicates that such a chirality transition occurs smoothly, accompanying the transition of the stacking orders of TLG, around the domain wall solitons. This result demonstrates the important and hitherto neglected relationship between the crystallographic stacking order and the chirality of quasiparticles in graphene systems.