Topological Exciton Fermi Surfaces in Two-Component Fractional Quantized Hall Insulators

Area of Science:

• Condensed Matter Physics
• Quantum Hall Effect
• Two-Dimensional Electron Systems

Background:

• Fractional quantum Hall (FQH) states in two-component systems allow independent charge density control.
• A recent experiment observed a continuous transition in bilayer graphene (BLG) at total filling ν_{T}=1/2, showing an incompressible phase with finite interlayer polarizability.

Purpose of the Study:

• To explain the origin of the finite interlayer polarizability in the incompressible phase at ν_{T}=1/2 in BLG.
• To investigate the role of interlayer excitons in the observed electronic phase transition.

Main Methods:

• Theoretical analysis of the topological order in ν_{T}=1/2 FQH states.
• Exact diagonalization studies to compare the energies of fermionic and bosonic excitons.

Main Results:

• The topological order supports novel interlayer excitons with Fermi statistics.
• Fermionic excitons are found to be lower in energy than conventional bosonic excitons.
• This suggests the formation of an emergent neutral Fermi surface, explaining the polarizable incompressible state.

Conclusions:

• A
• topological exciton metal
• hidden within a FQH insulator, may have been experimentally realized in BLG.
• The study proposes experimental schemes to detect this novel state.