A periodic array of cylindrical voids, embedded in a thin film of n-doped GaAs, displays a pronounced anisotropy of the classical magnetoresistance. For a geometry where the magnetic field lies in the plane of the film, we observe a characteristic dependence on the angle between current and magnetic field. This experimental finding provides a first verification of a recently predicted effect and agrees well with theoretical calculations. The observed anisotropy is due to interactions among current distortions by neighboring voids. [S0031-9007(96)00586-8]
The magnetoresistance of a two-dimensional electron system, subjected to a one-dimensional lateral potential modulation is studied for various potential amplitudes. The interplay between Landau level splitting and modulation broadening is shown to generate a transition from even to odd filling factors for the Shubnikov-de Haas resistance minima. The effect provides a tool to determine the potential amplitude. Calculations within a one-particle model agree with this evidence of the van Hove-like structure of the Landau bands.
Hall bars with widths down to about 250 nm were prepared by overgrowth on patterned GaAs(001) substrates using molecular beam epitaxy. This fabrication method generates a lateral confinement potential determined by AlGaAs barriers. The four-terminal magnetoresistance of a single wire, measured at 1.3 K after illumination, displays the well-known features of quasi-one-dimensional electron systems. We estimate the electron mobility in a ∼250 nm wide wire to be larger than 51 000 cm2/V s at a carrier concentration of 3.3×1011 cm−2.This mobility is comparable to the one measured in a wide reference sample fabricated under identical conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.