Landau level diagram and the continuous rotational symmetry breaking in trilayer graphene

TL;DR

This paper investigates the Landau level structure in ABA-stacked trilayer graphene, revealing how electric and magnetic fields influence the zeroth Landau levels and demonstrating symmetry breaking effects due to trigonal warping.

Contribution

It provides a quantitative estimation of electric field non-uniformity and determines the Landau level sequence, highlighting symmetry breaking in trilayer graphene.

Findings

Determined the sequence of zeroth Landau levels in ABA-stacked TLG.

Observed anticrossings caused by symmetry breaking from trigonal warping.

Quantified the non-uniform electric field in an ultraclean sample.

Abstract

The sequence of the zeroth Landau levels (LLs) between filling factors $\nu$=-6 to 6 in ABA-stacked trilayer graphene (TLG) is unknown because it depends sensitively on the non-uniform charge distribution on the three layers of ABA-stacked TLG. Using the sensitivity of quantum Hall data on the electric field and magnetic field, in an ultraclean ABA-stacked TLG sample, we quantitatively estimate the non-uniformity of the electric field and determine the sequence of the zeroth LLs. We also observe anticrossings between some LLs differing by 3 in LL index, which result from the breaking of the continuous rotational to \textit{C}$_3$ symmetry by the trigonal warping.