Electron Transport in Antidot Superlattices

Abstract

Antidot superlattices on semiconductor heterostructures represent a prototype to study superlattice phenomena in systems with reduced dimensionality. The repulsive potential of an antidot replaces the positively charged ion in a three-dimensional crystal leading to scattering of the carriers on the periodic lattice. The transport of electrons in antidot superlattices realized by different fabrication methods is reviewed. The focused ion beam technology can be used to create local damage to a two-dimensional electron gas in very small areas. The low magnetic field transport in this case is dominated by two length scales: the period of the lattice and the mean distance between two antidots that determines the total resistance of the system. Antidot systems with the locally repulsive potential resulting from electrostatic confinement favor the ballistic aspects of electron transport in a magnetic field. Thirdly, antidots can be created by low energy ion irradiation through a suitable photoresist grating in possible combination with homogeneous or nanostructured gate electrodes. This damage-type method allows to retain the high mobility of the electrons in the antidot lattice.