Fractional Topological States in Rhombohedral Multilayer Graphene Modulated by Kagome Superlattice

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Physics

Background:

• Fractional quantum anomalous Hall effects are actively researched in moiré heterostructures.
• Developing new platforms for realizing topological phases is crucial for quantum technologies.

Purpose of the Study:

• To propose and theoretically investigate rhombohedral multilayer graphene coupled with a kagome superlattice potential as a novel platform for fractional topological phases.
• To explore the electronic, topological, and quantum geometric properties of this system.

Main Methods:

• Theoretical study of electronic band structures and topological properties.
• Utilizing a tunable kagome superlattice potential on Bernal bilayer graphene.
• Employing exact diagonalization calculations for fractional fillings.

Main Results:

• Identification of nearly ideal topological flat bands in a wide parameter range.
• Observation of rich fractional topological phases (fractional Chern insulators, composite Fermi liquids) at various fractional fillings (1/3, 2/3, 2/5, 3/5, 1/2) without a magnetic field.
• Potential emergence of Halperin-type FCI states in trilayer graphene systems.

Conclusions:

• Rhombohedral multilayer graphene with a kagome superlattice potential offers a promising new platform for realizing diverse fractional topological phases.
• The findings pave the way for exploring novel quantum phenomena and potential applications in topological quantum computing.