Signatures of composite-fermion metals in electron bilayers at nu(T)=1

Composite-fermion metals occur in the quantum Hall bilayers at total Landau level filling fraction v(T) = 1 as the tunneling gap Delta(SAS) collapses by application of in-plane magnetic fields. Experimental evidence is obtained from the observation of a spin continuum below the Zeeman energy by resonant inelastic light scattering. These low-lying spin modes are assigned to quasi-particle excitations, where spin and composite-fermion Landau level index change simultaneously. (C) 2007 Elsevier B.V. All rights reserved.