We report the experimental realization of a correlated insulating phase in 2D
GaAs/AlGaAs heterostructures at low electron densities in a limited window of
background disorder. This has been achieved at mesoscopic length scales, where
the insulating phase is characterized by a universal hopping transport
mechanism. Transport in this regime is determined only by the average electron
separation, independent of the topology of background disorder. We have
discussed this observation in terms of a pinned electron solid ground state,
stabilized by mutual interplay of disorder and Coulomb interaction.Comment: 4+delta pages, 4 figures, To appear in the Physical Review B (Rapid
Comm