Topological phases in N -layer ABC graphene/boron nitride moiré superlattices

David Andrés Galeano González, Bheema Lingam Chittari, Youngju Park, Jin Hua Sun, Jeil Jung

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Rhombohedral N=3 trilayer graphene on hexagonal boron nitride hosts gate-tunable, valley-contrasting, nearly flat topological bands that can trigger spontaneous quantum Hall phases under appropriate conditions of the valley and spin polarization. Recent experiments have shown signatures of C = 2 valley Chern bands at 1/4 hole filling, in contrast to the predicted value of C = 3. We discuss the low-energy model for rhombohedral N-layer graphene (N = 1, 2, 3) aligned with hexagonal boron nitride subject to off-diagonal moiré vector potential terms that can alter the valley Chern numbers. Our analysis suggests that topological phase transitions of the flatbands can be triggered by pseudomagnetic vector field potentials associated to moiré strain patterns, and that a nematic order with broken rotational symmetry can lead to valley Chern numbers that are in agreement with recent Hall conductivity observations.

Original languageEnglish
Article number165112
JournalPhysical Review B
Volume103
Issue number16
DOIs
StatePublished - 12 Apr 2021

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