title: Imaging fractional incompressible stripes in integer quantum Hall systems.
abstract: Transport experiments provide conflicting evidence on the possible existence of fractional order within integer quantum Hall systems. In fact, integer edge states sometimes behave as monolithic objects with no inner structure, while other experiments clearly highlight the role of fractional substructures. Recently developed low-temperature scanning probe techniques offer today an opportunity for a deeper-than-ever investigation of spatial features of such edge systems. Here we use scanning-gate microscopy and demonstrate that fractional features were unambiguously observed in every integer quantum Hall constriction studied. We present also an experimental estimate of the width of the fractional incompressible stripes corresponding to filling factors 1/3, 2/5, 3/5, and 2/3. Our results compare well with predictions of the edge-reconstruction theory.
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Paradiso
authors.forename: Stefan
authors.initials: S
authors.lastname: Heun
authors.forename: Stefano
authors.initials: S
authors.lastname: Roddaro
authors.forename: Lucia
authors.initials: L
authors.lastname: Sorba
authors.forename: Fabio
authors.initials: F
authors.lastname: Beltram
authors.forename: Giorgio
authors.initials: G
authors.lastname: Biasiol
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: West