Transition between quantum Hall conductor and Hall insulator in Si MOSFET’s

We measured the conductor-insulator transition in a two-dimensional electron system in a Si metal-oxide-semiconductor field-effect transistor with low peak electron mobility μₚₑₐₖ=0.91 m²/V s and compared the results with those observed in a sample with μₚₑₐₖ=2.71 m²/V s. The behavior of σₓₓ and σxy at Landau-level filling factor {ν}=2 depends on a dimensionless parameter ωc{τ} in both samples. Here, ωc is the cyclotron frequency and {τ} is the relaxation time of an electron determined in the absence of magnetic field. Oscillations of phase boundaries in {ν}{}1 regions in the Nₛ-B plane are similar to each other. These observations show that the transition is caused by Anderson localization due to disorder, not by a formation of an electron solid.