Role of reversed spins in the correlated ground state for the fractional quantum Hall effect

The ground-state energy for the correlated liquid state of Laughlin with one-half of the electrons having spins antiparallel to the field is obtained at 2/5 filling of the lowest Landau level. The energy is found to be lower compared with the potential energy of the spin-polarized state. The energy difference is small, however, compared with the difference of magnetic energies between the two states under the present experimental conditions. Some of the results obtained for the one-spin state are in good agreement with recent experimental observations and very accurate Monte Carlo results.