Multicomponent Quantum Hall Ferromagnetism and Landau Level Crossing in Rhombohedral Trilayer Graphene

TL;DR

This study explores the complex quantum Hall ferromagnetism in rhombohedral trilayer graphene, revealing how spin, orbital, and layer pseudospins spontaneously order and how Landau level degeneracies are lifted under various conditions.

Contribution

It provides new insights into the multicomponent quantum Hall ferromagnetism and Landau level crossings in rhombohedral trilayer graphene, highlighting the role of interlayer potential and symmetry breaking.

Findings

Observation of intermediate quantum Hall plateaus.

Complete lifting of zeroth Landau level degeneracy.

Hexagon pattern in phase space explained by LL crossings.

Abstract

Using transport measurements, we investigate multicomponent quantum Hall (QH) ferromagnetism in dual-gated rhombohedral trilayer graphene (r-TLG), in which the real spin, orbital pseudospin and layer pseudospins of the lowest Landau level form spontaneous ordering. We observe intermediate quantum Hall plateaus, indicating a complete lifting of the degeneracy of the zeroth Landau level (LL) in the hole-doped regime. In charge neutral r-TLG, the orbital degeneracy is broken first, and the layer degeneracy is broken last and only the in presence of an interlayer potential U. In the phase space of U and filling factor, we observe an intriguing hexagon pattern, which is accounted for by a model based on crossings between symmetry-broken LLs.