Chiral symmetry breaking and topological charge of graphene nanoribbons

• URL: http://arxiv.org/abs/2312.05487v3
• Date: Fri, 22 Mar 2024 12:54:23 GMT
• Title: Chiral symmetry breaking and topological charge of graphene nanoribbons
• Authors: Hyun Cheol Lee, S. -R. Eric Yang,
• Abstract summary: We explore the edge zigzag properties of rectangular graphene nanoribbons featuring two edges and two armchair edges. Although the self-consistent Hartree-Fock fields break chiral symmetry, our work demonstrates that graphene nanoribbons maintain their status as short-range entangled symmetry-protected topological insulators.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We explore the edge properties of rectangular graphene nanoribbons featuring two zigzag edges and two armchair edges. Although the self-consistent Hartree-Fock fields break chiral symmetry, our work demonstrates that graphene nanoribbons maintain their status as short-range entangled symmetry-protected topological insulators. The relevant symmetry involves combined mirror and time-reversal operations. In undoped ribbons displaying edge ferromagnetism, the band gap edge states with a topological charge form on the zigzag edges. An analysis of the anomalous continuity equation elucidates that this topological charge is induced by the gap term. In low-doped zigzag ribbons, where the ground state exhibits edge spin density waves, this topological charge appears as a nearly zero-energy edge mode. Our system is outside the conventional calssification for topological insulators.

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