Quasiparticles in the 111 state and its compressible ancestors

We investigate the relationship of the spontaneously interlayer coherent ‘‘111’’ state of quantum Hall bilayers at total filling factor n51 to ‘‘mutual’’ composite fermions, in which vortices in one layer are bound to electrons in the other. Pairing of the mutual composite fermions leads to the low-energy properties of the 111 state, as we explicitly demonstrate using field-theoretic techniques. Interpreting this relationship as a mechanism for interlayer coherence leads naturally to two candidate states with nonquantized Hall conductance: the mutual composite Fermi liquid and an interlayer coherent charge e Wigner crystal. The experimental behavior of the interlayer tunneling conductance and resistivity tensors are discussed for these states.