title: The local nature of incompressibility of quantum Hall effect.
abstract: Since the experimental realization of the integer quantum Hall effect in a two-dimensional electron system, the interrelation between the conductance quantization and the topological properties of the system has been investigated. Assuming that the two-dimensional electron system is described by a Bloch Hamiltonian, system is insulating in the bulk of sample throughout the quantum Hall plateau due to a magnetic field induced energy gap. Meanwhile, the system is conducting at the edges resembling a 2+1 dimensional topological insulator without time-reversal symmetry. Here, by our magneto-transport measurements performed on GaAs/AlGaAs high purity Hall bars with two inner contacts we show that incompressible strips formed at the edges result in Hall quantization, even if the bulk is compressible. Consequently, the relationship between the quantum Hall effect and topological bulk insulator breaks for specific field intervals within the plateaus. The measurement of conducting bulk, strongly challenges all existing single-particle theories.
authors.affiliation: Faculty of Science, Department of Physics, Istanbul University, Vezneciler, Istanbul 34134, Turkey.
authors.forename: E M
authors.initials: EM
authors.lastname: Kendirlik
authors.affiliation: Department of Physics, Science and Letters Faculty, Mimar Sinan Fine Arts University, Sisli, Istanbul 34380, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Sirt
authors.affiliation: Faculty of Science, Department of Physics, Istanbul University, Vezneciler, Istanbul 34134, Turkey.
authors.forename: S B
authors.initials: SB
authors.lastname: Kalkan
authors.affiliation: Department of Applied Physics, Yale University, 217 Prospect Street New Haven, Connecticut 06511-8499, USA.
authors.forename: N
authors.initials: N
authors.lastname: Ofek
authors.affiliation: Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: V
authors.initials: V
authors.lastname: Umansky
authors.affiliation: Faculty of Science, Department of Physics, Istanbul University, Vezneciler, Istanbul 34134, Turkey.|Department of Physics, Science and Letters Faculty, Mimar Sinan Fine Arts University, Sisli, Istanbul 34380, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Siddiki