Novel magneto-resistance oscillations in laterally modulated two-dimensional electrons with 20 nm periodicity formed on vicinal GaAs (1 1 1)B substrates

Abstract

Laterally modulated two-dimensional electron gas has been formed in quasi-periodically corrugated AlGaAs/GaAs heterojunctions, where multi-atomic steps with about 20 nm periodicity are generated by growing GaAs epi-layer on vicinal (1 1 1)B substrates. We have measured two- and multi-terminal magneto-resistance R x perpendicular to the steps and R y parallel to them, and found novel oscillations different from the ordinary Shubnikov–de Haas oscillations. In the oscillation, R y has exhibited peaks at magnetic fields where R x shows minima, revealing the phase shift of 180° between them. We speculate that this anomaly is caused by van Hove singularity in the density of states of Landau subband in the periodically modulated system.