Influence of interlayer tunneling on the quantized Hall phases in intentionally disorderedmultilayer structures

Abstract

Stability of the quantized Hall phases is studied in weakly coupled multilayers as a functionof the interlayer correlations controlled by the interlayer tunneling and by the randomvariation of the well thicknesses. A strong enough interlayer disorder destroys thesymmetry responsible for the quantization of the Hall conductivity, resulting in thebreakdown of the quantum Hall effect. A clear difference between the dimensionalities ofthe metallic and insulating quantum Hall phases is demonstrated. The sharpness of thequantized Hall steps obtained in the coupled multilayers with different degrees ofrandomization was found consistent with the calculated interlayer tunneling energies. Theobserved width of the transition between the quantized Hall states in randommultilayers is explained in terms of the local fluctuations of the electron density.