A poly(styrene-block-methylmethacrylate) diblock copolymer in the hexagonal cylindrical phase has been used as a mask for preparing a periodic gate on top of a Ga[Al]As-heterostructure. A superlattice period of 43 nm could be imposed onto the two-dim
ensional electron gas. Transport measurements show a characteristic positive magnetoresistance around zero magnetic field which we interpret as a signature of electron motion guided by the superlattice potential.
