Electron transport through antidot superlattices in Si/Si0.7Ge0.3heterostructures

Transport properties of electrons in antidot superlattices are studied in Si/Ge heterostructures. Lateral superlattices with periods between 830 and 500 nm were imposed upon high-mobility two-dimensional electron gases in Si/${\mathrm{Si}}_{0.7}$ ${\mathrm{Ge}}_{0.3}$ heterostructures by means of laser holography and reactive ion etching. Typical features known from GaAs/${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As samples, such as low-field commensurability oscillations in the longitudinal resistivity ${\mathrm{\rho }}_{\mathit{x}\mathit{x}}$, additional nonquantized Hall plateaus, and quenching of the Hall effect around B=0, are observed. From the position of the commensurability maxima in ${\mathrm{\rho }}_{\mathit{x}\mathit{x}}$ we conclude that the lateral potential is rather smooth.