Spin‐Singlet Pairing of Composite Fermions

Interactions between composite fermions in a two-dimensional electron gas in a strong perpendicular magnetic field at a Landau level filling factor 1/2 are investigated. It is shown that for antiparallel spins and momenta of the quasi-particles the interplay between Coulomb interaction and fluctuations of the gauge field leads to an attractive effective interaction in the long-wavelength limit. It is argued that this can give rise to a ground state of spin-singlet pairs. A quantitative estimate for the pair-breaking gap is provided. Experimental implications are discussed.