  The composite fermion formalism elegantly describes some of the most
fascinating behaviours of interacting two-dimensional carriers at low
temperatures and in strong perpendicular magnetic fields. In this framework,
carriers minimize their energy by attaching two flux quanta and forming new
quasi-particles, the so-called composite fermions. Thanks to the flux
attachment, when a Landau level is half-filled, the composite fermions feel a
vanishing effective magnetic field and possess a Fermi surface with a
well-defined Fermi contour. Our measurements in a high-quality two-dimensional
hole system confined to a GaAs quantum well demonstrate that a parallel
magnetic field can significantly distort the hole-flux composite fermion Fermi
contour.
