Solitons in Rhombohedral Graphite

The vertical stacking of rhombohedral graphite resembles the Su-Schrieffer-Heeger (SSH) model, with alternating intra- and interlayer hopping mimicking the role of alternating hopping in the SSH model. Surface states with flat bands at low energy in rhombohedral graphite correspond to edge states in the SSH model. Structural stacking faults in rhombohedral graphite have additional bands at low energy which are localized at the faults [1], in analogy to solitons (domain walls) in the SSH model. However, such stacking faults in rhombohedral graphite always create a pair of energy bands, being equivalent to a combination of a soliton and anti-soliton. Here we discuss the possibility of realizing the equivalent of a single soliton with a single energy band in rhombohedral graphite. We discuss the parameter range under which such solitons exist and we described their topological properties.

[1] James H. Muten, Alex J. Copeland, and Edward McCann. “Exchange interaction, disorder, and stacking faults in rhombohedral graphene multilayers”. In: Phys. Rev. B 104 (3 2021), p. 035404. doi: 10.1103/PhysRevB.104.035404.