We report on a finite-size Hartree-Fock study of the competition between disorder and interactions in a two-dimensional electron gas near Landau-level filling factor $\nu =1.\mathrm{}$ The ground state at $\nu =1\mathrm{}$ evolves with increasing disorder from a fully spin-polarized ferromagnet with a charge gap to a partially spin-polarized ferromagnetic Anderson insulator, to a quasimetallic paramagnet at the critical point between $i=0\mathrm{}$ and $i=2\mathrm{}$ quantum Hall plateaus. Away from $\nu =1,$ the ground state evolves from a ferromagnetic Skyrmion quasiparticle glass to a conventional quasiparticle glass, and finally to a conventional Anderson insulator. We comment on signatures of these different regimes in low-temperature transport and NMR line shape and peak position data.

• Received 19 April 2000

DOI:https://doi.org/10.1103/PhysRevB.62.13579