Large composite fermion effective mass at filling factor 5/2

Area of Science:

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

Background:

• The 5/2 fractional quantum Hall effect in the second Landau level is a prime candidate for hosting non-Abelian anyons.
• These anyons are predicted to enable fault-tolerant quantum computations.
• The thermodynamic properties and effective mass of its composite fermion (CF) normal phase remain largely unknown.

Purpose of the Study:

• To investigate the thermodynamic properties of the composite fermion (CF) phase at the 5/2 fractional quantum Hall effect.
• To determine the effective mass of quasiparticles in this system.
• To understand the implications for potential quantum computing applications.

Main Methods:

• Time-resolved specific heat measurements at filling factor 5/2.
• Analysis of the ratio of specific heat to temperature.
• Integration of specific heat data with existing longitudinal thermopower data for entropy calculation.

Main Results:

• Specific heat measurements combined with entropy data suggest a large effective mass in the composite fermion (CF) Fermi liquid phase at 5/2.
• The estimated effective-to-bare mass ratio (m*/m_e) ranges from approximately 2 to 4.
• This effective mass is significantly larger (2-3 times) than values observed in the first Landau level.

Conclusions:

• The findings indicate a substantial effective mass for composite fermions (CFs) at the 5/2 fractional quantum Hall effect.
• This large effective mass has implications for the behavior of topological quasiparticles and their suitability for quantum computation.
• Further research is needed to fully elucidate the thermodynamic landscape and potential phase transitions.