Low-field magnetotransport study of localization in a mesoscopic antidot array.

Low-field negative magnetoresistance has been studied on G a + ion focused-ion-beam-patterned GaAs/Ga 1-x Al x As heterojunctions as a function of carrier density and temperature. The negative magnetoresistance (NMR) is very large at low densities and decreases with increasing carrier density, giving a magnetoconductance linear in T at low densities but closer to a lnT dependence at higher values. The NMR of this grid structure is well explained using weak localization modified by boundary scattering in an array of one-dimensional point contacts