Signatures of a Novel Fermi Liquid in a Two-Dimensional Composite Particle Metal

Abstract

Quasiparticle excitation gaps of the $\ensuremath{\nu}=\frac{p}{(2p+1)}$ fractional quantum Hall states in a low-disorder two-dimensional hole system are observed to scale linearly with $\frac{(\frac{{e}^{2}}{\ensuremath{\epsilon}{\ensuremath{\ell}}_{B}})}{(2p+1)}$, predicted by the Chern-Simons gauge field theory if a hole-flux composite particle Fermi liquid forms around filling $\ensuremath{\nu}=\frac{1}{2}$ (${\ensuremath{\ell}}_{B}$ is the magnetic length). The effective mass and quantum lifetime of these new particles reveal a remarkable renormalization structure, including a strongly diverging mass and enhanced scattering close to the Fermi surface, suggesting a novel class of marginal Fermi liquid behavior.