Stacking-Dependent Band Gap and Quantum Transport in Trilayer Graphene

TL;DR

This study reveals how stacking order in trilayer graphene dramatically affects its electronic transport, with ABC stacking showing an intrinsic gap and unique quantum Hall features, unlike ABA stacking.

Contribution

It demonstrates the distinct electronic transport behaviors in trilayer graphene based on stacking order, highlighting the presence of an intrinsic gap and Lifshitz transition signatures in ABC stacking.

Findings

ABA remains metallic at the Dirac point

ABC exhibits an intrinsic gap of ~6 meV

ABC shows Lifshitz transition signatures in quantum Hall measurements

Abstract

In a multi-layer electronic system, stacking order provides a rarely-explored degree of freedom for tuning its electronic properties. Here we demonstrate the dramatically different transport properties in trilayer graphene (TLG) with different stacking orders. At the Dirac point, ABA-stacked TLG remains metallic while the ABC counterpart becomes insulating. The latter exhibits a gap-like dI/dV characteristics at low temperature and thermally activated conduction at higher temperatures, indicating an intrinsic gap ~6 meV. In magnetic fields, in addition to an insulating state at filling factor {\nu}=0, ABC TLG exhibits quantum Hall plateaus at {\nu}=-30, \pm 18, \pm 9, each of which splits into 3 branches at higher fields. Such splittings are signatures of the Lifshitz transition induced by trigonal warping, found only in ABC TLG, and in semi-quantitative agreement with theory. Our results underscore the rich interaction-induced phenomena in trilayer graphene with different stacking orders, and its potential towards electronic applications.