In condensed-matter physics, a composite fermion is the bound state of an electron and an even number of quantized vortices, sometimes modelled as an electron with an even number of magnetic flux quanta attached to it. They were introduced in 1989 by J. K. Jain to explain the fractional quantum Hall effect as the integral quantum Hall effect of composite fermions.
Composite fermions are the quasiparticles of the fractional quantum Hall effect, a phenomenon that occurs when electrons are confined to two dimensions and exposed to a strong magnetic field. Composite fermions are formed because electrons can keep apart most effectively by dressing themselves with quantized vortices.
The principal property of composite fermions is that they experience a magnetic field that is much smaller than the external magnetic field (and can even point in the opposite direction). The integral quantum Hall effect of composite fermions manifests as the fractional quantum Hall effect of electrons. Composite fermions also form other states, the most notable being a Fermi sea and a paired state akin to superconductivity of electrons.
Further reading
edit- J. K. Jain. Composite Fermions. Cambridge University Press, 2007. ISBN 9780521862325
- O. Heinonen. Composite Fermions: A Unified View of the Quantum Hall Regime. World Scientific Publishing Company, 1998. ISBN 9789812384133