DESTRUCTION OF THE QUANTUM HALL EFFECT WITH INCREASING DISORDER

Abstract

We report experimental studies of disorder-induced transitions between quantum-Hall, metallic, and insulating states in a very dilute two-dimensional electron system in silicon at a magnetic field corresponding to Landau level filling factor $\nu =1$. At low disorder, the lowest extended state at $\nu =1$ is below the Fermi energy so that the system is in the quantum Hall state. Our data show that with increasing disorder (but at constant electron density and magnetic field), the extended state DOES NOT DISAPPEAR BUT FLOATS UP IN ENERGY SO THAT THE SYSTEM BECOMES INSULATING. As the extended state crosses the Fermi energy, the conductivity ${\sigma }_{xx}\sim e^2/2h$ has temperature dependence characteristic of a metallic system.

REVTeX file; 4 postscript figures on request; to appear in PRB

Cited by in corpus (9)

• Floating of Extended States and Localization Transition in a Weak Magnetic Field
• Landau Level Mixing and Levitation of Extended States in Two Dimensions
• Quantum Hall - insulator transitions in lattice models with strong disorder
• The fate of interaction-driven topological insulators under disorder
• Short--range impurity in the vicinity of a saddle point and the levitation of the 2D delocalized states in a magnetic field
• Integer Quantum Hall Effect: Disorder, temperature, floating, and plateau width
• Emergent space-time supersymmetry at disorder quantum critical point
• Quasiclassical approach to the weak levitation of extended states in the quantum Hall effect
• Two-loop disorder effects on the nematic quantum criticality in $d$-wave superconductors