Density of states in a two-dimensional electron gas in the presence of a one-dimensional superlattice potential

Magnetocapacitance measurements are performed on a holographically microstructured ${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$-GaAs heterostructure, in order to obtain direct information about the density of states of a periodically modulated two-dimensional electron gas. Comparison with microscopic calculations shows that the observed pronounced modulation of the magnetocapacitance oscillations has the same origin as the novel resistance oscillations recently reported for this system.