title: Mode Specific Backscattering in a Quantum Point Contact.
abstract: We demonstrate a scanning gate grid measurement technique consisting in measuring the conductance of a quantum point contact (QPC) as a function of gate voltage at each tip position. Unlike conventional scanning gate experiments, it allows investigating QPC conductance plateaus affected by the tip at these positions. We compensate the capacitive coupling of the tip to the QPC and discover that interference fringes coexist with distorted QPC plateaus. We spatially resolve the mode structure for each plateau.
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: A A
authors.initials: AA
authors.lastname: Kozikov
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Steinacher
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Rössler
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Ihn
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Ensslin
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Reichl
authors.affiliation: Solid State Physics Laboratory, ETH Zürich , CH-8093 Zürich, Switzerland.
authors.forename: W
authors.initials: W
authors.lastname: Wegscheider
keywords: GaAs; Scanning gate microscopy; ballistic transport; quantum point contact