Experimental observation of an artificial band structure in lateral superlattices

Abstract

Short period lateral superlattices are fabricated on AlGaAs/GaAs-Heterostructures by electron beam lithography. The samples are experimentally investigated by low temperature magneto transport experiments. For small values of the lateral potential modulation, the amplitude of the Shubnikov-de Haas oscillation is modulated, reflecting the oscillating band width of the Landau bands. For increasing values of the potential modulation the Landau band width increases, and the internal structure of the Landau bands is resolved. In particular, a splitting of the maxima of SdH oscillation is observed and attributed to the dominant energy bands and gaps within the Hofstadter Butterfly energy spectrum. These experiments constitute the experimental observation of band structure effects, arising from an artificially imposed superlattice potential.