Quantum Hall ferromagnet in a parabolic quantum wire

The spin phase diagram of interacting electrons in a quantum wire under a high magnetic field is investigated by finite-system exact,diagonalization. Various phases emerge as a function of interaction strength and aspect ratio. Stable spin-polarized states correspond to two-dimensional fractional quantum Hall states of filling fractions 1/q, with q odd. Spin-singlet ground states for six electrons with filling fractions around 2/5-1/2 are inspected in detail, and a real-space singlet pairing state peculiar to wire systems is found for a larger aspect ratio. [S0163-1829(98)06640-5].