Anisotropic transport of unidirectional lateral superlatticearound half filling of N ≥ 1 Landau levels

摘要

We report anisotropic transport features appearing around half filling of N ≥ 1Landau levels, prompted by very small but well-defined periodic external modulation. Inmost cases, a peak (a dip) appears for current along (across) the grating that introduces themodulation. We interpret the observed transport anisotropy as a manifestation, assisted bythe external modulation, of the unidirectional charge density wave or stripe state, which istheoretically predicted to be the ground state of half-filled high Landau levels.