Observation of the quantum Hall effect in cleaved InAs surfaces

We have performed the in-plane magnetotransport measurements on the two-dimensional electron gas at the cleaved p-InAs (1 1 0) surface by deposition of Ag. The surface electron density Ns is determined from the Hall coefficient at View the MathML source. The coverage dependence of Ns is well explained by the assumption that each adsorbed Ag atom denotes one electron into InAs until the surface Fermi level reaches the adsorbate-induced donor level. The electron mobility μ is about View the MathML source and does not show a clear dependence on the coverage over View the MathML source. In the high-magnetic field regime of B>1/μ, Shubnikov–de Hass oscillations were observed. A beating pattern due to the strong spin–orbit interaction appears for high Ns. For lower Ns of View the MathML source, an apparent quantum Hall plateau for ν=4 and vanishing of the longitudinal resistivity were observed around View the MathML source.