Emergent Gauge Field in Composite-Fermion Metals: A Large-Scale Microscopic Study

Area of Science:

• Condensed Matter Physics
• Quantum Hall Effect
• Many-Body Theory

Background:

• Composite fermion (CF) theories model metals as a Fermi sea of CFs interacting with an emergent gauge field.
• Previous theories predicted Landau damping would induce a q³lnq correction to the static structure factor S(q) in CF metals.
• Accurate microscopic calculations of S(q) were previously limited by system size.

Purpose of the Study:

• To investigate the small-q behavior of the static structure factor S(q) in composite fermion (CF) metals.
• To compare microscopic calculation results with theoretical predictions and simplified models.
• To explore CF metals at various Landau level filling factors (ν=1/2, 1/4) and bosonic systems (ν=1, 1/3).

Main Methods:

• Utilized a recently developed quaternion formulation for Jain-Kamilla projection of CF wave functions.
• Performed microscopic calculations of S(q) for systems up to N=900 CFs.
• Analyzed the low-energy, long-wavelength behavior of S(q) in the q→0 limit.

Main Results:

• Microscopic calculations revealed a q³ term in S(q) for CF metals, contradicting the predicted q³lnq correction.
• The observed q³ behavior was accurately reproduced by a model of a noninteracting Fermi sea of dipolar CFs.
• The coefficient of the q³ term was also accurately obtained by the dipolar CF model.

Conclusions:

• The Landau damping effect in CF metals does not lead to the predicted q³lnq correction to S(q).
• A simple model of noninteracting dipolar composite fermions accurately describes the small-q behavior of S(q).
• This work provides a reliable determination of S(q) from accurate microscopic theory for larger systems.