Tunneling, dissipation, and superfluid transition in quantum Hall bilayers.

Area of Science:

• Condensed Matter Physics
• Quantum Hall Effect
• Superfluidity

Background:

• Bilayer quantum Hall systems exhibit complex behavior at specific filling factors.
• Interlayer tunneling and coupling to a normal fluid significantly influence system dynamics.
• Understanding phase transitions is crucial for quantum Hall effect research.

Purpose of the Study:

• To investigate the role of interlayer tunneling and dissipation in bilayer quantum Hall systems at nu=1.
• To determine the critical dissipation level governing system phase transitions.
• To analyze the resulting phase structure and current behaviors.

Main Methods:

• Modeling the interlayer phase dynamics using an effective quantum dissipative XY model.
• Analyzing the system's behavior above and below a critical dissipation threshold.
• Connecting theoretical findings to experimental observations.

Main Results:

• A critical dissipation (sigma(c)) was identified, dependent on normal fluid conductance.
• Above sigma(c), interlayer tunneling leads to a nu=1 quantum Hall state.
• Below sigma(c), an excitonic superfluid transition to a collective quantum Hall state occurs at low temperatures.

Conclusions:

• Dissipation plays a critical role in determining the low-temperature phase of bilayer quantum Hall systems.
• The study reveals distinct quantum Hall and excitonic superfluid states based on dissipation levels.
• The findings provide insights into phase structure and current dynamics relevant to experimental studies.