TOPOLOGICAL DEFECTS, ORIENTATIONAL ORDER, AND DEPINNING OF THE ELECTRON-SOLID IN A RANDOM POTENTIAL

Two-dimensional classical electron solids under the influence of modul ation-doped impurities are studied by using a molecular dynamics metho d. We find that in the strong disorder limit the ground state configur ation contains both isolated dislocations and disclinations, whereas i n the weak disorder regime only dislocations are present. We show, via continuum elasticity theory, that the ground state of the lattice sho uld be unstable against a proliferation of free disclinations above a critical dislocation density. Associated with this, the behavior of th e depinning electric field changes.