Modulation induced stripe phase at fractional fillings

We have experimentally examined the state of a two-dimensional electron gas subjected to unidirectional periodic potential modulation in the vicinity of the filling ν=5/3 (equivalent to ν=1/3 by the particle-hole symmetry). In addition to a peak in the longitudinal resistivity ρ_xx, we find small amplitude oscillations roughly periodic in the magnetic field B in the Hall resistivity ρ_yx. The oscillations appear in a narrow range of the electron density n_e, and the period ΔB of the oscillations increases with the slight increase in n_e. The oscillations are interpreted as resulting from the commensurability between the high harmonics of the modulation potential and the stripe state, which is predicted by the density matrix renormalization group calculations to be the ground state in our system.