title: Conductance maps of quantum rings due to a local potential perturbation.
abstract: We performed a numerical simulation of the dynamics of a Gaussian shaped wavepacket inside a small sized quantum ring, smoothly connected to two leads and exposed to a perturbing potential of a biased atomic force microscope tip. Using the Landauer formalism, we calculated conductance maps of this system in the case of single and two subband transport. We explain the main features in the conductance maps as due to the AFM tip influence on the wavepacket phase and amplitude. In the presence of an external magnetic field, the tip modifies the ϕ0 periodic Aharonov-Bohm oscillation pattern into a ϕ0/2 periodic Al'tshuler-Aronov-Spivak oscillation pattern. Our results in the case of multiband transport suggest tip selectivity to higher subbands, making them more observable in the total conductance map.
authors.affiliation: Department of Physics, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium.
authors.forename: M D
authors.initials: MD
authors.lastname: Petrović
authors.forename: F M
authors.initials: FM
authors.lastname: Peeters
authors.forename: A
authors.initials: A
authors.lastname: Chaves
authors.forename: G A
authors.initials: GA
authors.lastname: Farias