Topological states in double monolayer graphene

TL;DR

This paper explores novel topological states in double monolayer graphene with different areas, revealing excitations with fractional statistics but integer charges, expanding understanding of quantum Hall phenomena.

Contribution

It introduces a new class of topological states in double monolayer graphene with unequal areas, featuring excitations obeying fractional statistics without fractional charges.

Findings

Some states can be realized with realistic parameters.

Elementary excitations obey fractional statistics.

Distinct from traditional fractional quantum Hall states.

Abstract

Motivated by the experiments on double monolayer graphene that observe a variety of fractional quantum Hall states [Liu et al., Nat. Phys. 15, 893 (2019); Li et al., Nat. Phys. 15, 898 (2019)], we study the special setting in which two monolayers have different areas. It has not been considered before and allows us to construct a class of exotic topological states. The elementary excitations of these states do not carry fractional charges but obey fractional statistics. This is in sharp contrast to all previously studied cases, where the two properties are intimately connected and serve as hallmarks of fractional quantum Hall states. Numerical calculations are performed to demonstrate that some states can be realized with realistic parameters.