INSULATOR-TO-QUANTUM-HALL-LIQUID TRANSITION IN AN ANTIDOT LATTICE

Measurements are reported of the Hall resistance rho(xy) and magnetore sistance rho(xx) of a two-dimensional electron gas containing a triang ular lattice of approximately circular depleted regions (antidots). Th e transition from insulator to quantum Hall liquid shows a fixed point where the longitudinal resistance is independent of temperature; scal ing exponents are determined. rho(xx) and rho(xy) oscillate with magne tic flux through the unit cell of the antidot lattice, although the di ssipation results from hopping between localized states.