Anisotropic mobilities of low-dimensional electrons at stepped n-AlGaAs/GaAs interfaces with 15 nm periodicity on vicinal (111)B substrates

Laterally modulated two-dimensional electron systems with 15 nm periodicity have been formed at n-AlGaAs/GaAs heterojunctions by making use of multi-atomic steps formed on vicinal (1 1 1)B GaAs epilayers. Highly anisotropic electron mobilities have been observed, where mobility μ|| parallel to the steps increases monotonically up to View the MathML source with carrier density Ns at 4.2 K while mobility μ⊥ perpendicular to the steps decreases remarkably to View the MathML source at high Ns. By comparing this experimental result with theory, we have found that a periodic component of the in-plane potential is important for the anisotropy.