Orbital Lamb shift and mixing of the pseudo-zero-mode Landau levels in ABC-stacked trilayer graphene

TL;DR

This paper investigates how Coulomb interactions cause orbital Lamb shifts and mixing of zero-energy Landau levels in ABC-stacked trilayer graphene, revealing effects similar to bilayer graphene but with richer symmetry considerations.

Contribution

It extends the concept of orbital Lamb shift and level mixing from bilayer to ABC-stacked trilayer graphene, highlighting the enriched symmetry and potential experimental implications.

Findings

Orbital Lamb shift occurs in ABC-stacked trilayer graphene.

Zero-mode Landau levels experience mixing due to Coulomb interactions.

Results align with and provide insights into recent experimental observations.

Abstract

In a magnetic field graphene trilayers support a characteristic multiplet of 12 zero(-energy)-mode Landau levels with a threefold degeneracy in Landau orbitals. It was earlier noted for bilayer graphene that Coulombic vacuum fluctuations, specific to graphene, lift the orbital degeneracy of such zero-energy modes and that these Lamb-shfted" orbital modes, with filling, get mixed via the Coulomb interaction. It is pointed out that analogous orbital Lamb shift and mixing of zero-mode levels can also take place, with an enriched symmetry content, in ABC-stacked trilayer graphene; and its consequences are discussed in the light of experimental results.