Unusually Wide Plateau of the Quantum Hall Effect in a Quad Bilayer Hole System Inside the p-GeSi/Ge/p-GeSu Quantum Well.

摘要

An unusually wide plateau of the integer quantum Hall effect (for the filling factor nu = 1) has been revealed in a wide p-GeSi/Ge/p-GeSi quantum well. This plateau exists in one of two metastable states of the sample, for which a symmetric quasi-double-quantum-well system is formed inside the Ge layer due to the hole-hole repulsion. The plateau exists not only within a magnetic field range corresponding to the quantum-Hall liquid, but extends beyond it into a so-called quantized Hall insulator phase. According to the existing theories. this extra wide plateau may be indicative of a kind of disorder. characterized by a certain distribution of fluctuations in their size and carrier density.