Disorder-Driven Transition in the ν=5/2 Fractional Quantum Hall Effect

Area of Science:

• Condensed Matter Physics
• Topological Quantum Matter
• Quantum Hall Effect

Background:

• The fractional quantum Hall (FQH) effect at ν=5/2 is a key candidate for non-Abelian topological order.
• The impact of disorder on this exotic FQH state remains an unresolved fundamental question.

Purpose of the Study:

• To investigate the fate of the ν=5/2 FQH state under random disorder.
• To characterize the phase transitions and emergent phases driven by increasing disorder strength.

Main Methods:

• Unbiased diagnosis using numerical exact diagonalization.
• Calculation of disorder-averaged Hall conductance and Chern number distributions.
• Analysis of wave function fidelity and entanglement entropy to detect phase transitions.

Main Results:

• Disorder drives a continuous phase transition, leading to the collapse of the FQH state.
• A composite Fermi liquid phase with fluctuating Chern numbers emerges in the strong disorder regime.
• An intermediate phase, potentially linked to Pfaffian states, is identified via multiple probes.

Conclusions:

• The ν=5/2 FQH state exhibits a distinct response to disorder compared to the ν=1/3 state.
• The findings reveal a complex interplay between topology, disorder, and emergent phases in strongly correlated electron systems.