COHERENT MAGNETOTRANSPORT IN CONFINED ARRAYS OF ANTIDOTS .2. 2-TERMINAL CONDUCTANCE

The magnetoconductance due to coherent transport through antidot array s in confined (strip) geometries is investigated. Our hybrid Green-fun ction method is adapted to the calculation of the transport properties of such systems. A simple derivation of the surface Green function in a magnetic field is provided, The two-terminal conductance of antidot arrays is analyzed on the basis of their magnetoband structure. At re latively low magnetic fields the conductance (in units of 2e(2)/h) app roximately follows the number of states (NOS) of the corresponding inf inite structure, with a steplike oscillatory dependence on the magneti c field superimposed onto a slow background variation. The Fourier pow er spectra of the magnetoconductance and NOS curves reveal that the pe riodicity is related to the basic Aharonov-Bohm frequency of the syste m. Around the field value at which the cyclotron diameter equals the l attice constant of the array, the magnetoresistance has a broad maximu m. Also at about a quarter of this field value a broad maximum can be detected. These results agree with experimental findings. The broad ma xima are usually attributed to resonances with electron states trapped around single and groups of four antidots. An alternative interpretat ion, in better agreement with the facts, is proposed. At high fields, simple edge state transport at the boundaries of the array takes over.