Anomalous density dependence of anisotropic resistivity at half-filling of N⩾2 Landau levels in short-period unidirectional lateral superlattice

A short-period (period View the MathML source) unidirectional lateral superlattice with a uniform back gate has been used to investigate detailed dependence of anisotropic transport in N⩾2 Landau levels on electron density ne. Within rather narrow ne range of 1.85–View the MathML source, resistance peaks of quantum Hall transition regions are observed to grow (diminish) rapidly with ne for the current across (along) the superlattice. The peak between filling factors 4 and 5 starts to split above View the MathML source for the current across the superlattice, with the valley in between showing thermally activated temperature dependence with gap energy View the MathML source. The observed behavior of anisotropic transport suggests the relevance of the theoretically predicted charge density wave state.