Fractional Quantum Hall Features in the Quantum Limit

The interest in transport properties of a 2D electron gas in the magnetic quantum limit has recently focused on the possibility of a phase transition from quantum liquid states of the fractional quantum Hall effect (FQHE) to a magnetic field-induced electron solid as the Landau level filling factor v is lowered. The evidence for the formation of such a Wigner solid remains controversial since alternative interpretations of the experimental data exist. Under such confusing circumstances we have focused on the filling factor v=1/5 in order to resolve the question of Wigner solid versus FQHE. A similarly unresolved question concerns the wide feature in rho sub (xx) around v=1/2 which differs characteristically from the sharp minima associated with the FQHE. From recent finite size calculations, it is speculated that there may exist a `Wigner-lattice-like` state which may be deformable. With our transport experiments we tried to shed some light on the state around v=1/2.