Anisotropic transport of unidirectional lateral superlattice in high Landau levels

Abstract

We report anisotropic transport observed in unidirectional lateral superlattices (LSL) with period a=92 nm , at high (6⩾ N⩾1) Landau levels (LLs). Near the half-filling of the LLs (up to filling factor ν= 25 2 ), sharp peaks are observed in the resistance traces when current is along the grating that defines the superlattice, which are not present (sometimes dips appear) for current across the grating. The peaks show alternating intensities with magnetic field: higher-magnetic-field branch spin sublevels in each LL tend to display more distinct peaks. Since the period a of LSL is close to the theoretically predicted period of the stripe phase in half-filled high LLs, the observed peaks probably represent the response of the stripe to the external periodic modulation.