title: Spin-Flip and Element-Sensitive Electron Scattering in the BiAg2 Surface Alloy.
abstract: Heavy metal surface alloys represent model systems to study the correlation between electron scattering, spin-orbit interaction, and atomic structure. Here, we investigate the electron scattering from the atomic steps of monolayer BiAg_{2} on Ag(111) using quasiparticle interference measurements and density functional theory. We find that intraband transitions between states of opposite spin projection can occur via a spin-flip backward scattering mechanism driven by the spin-orbit interaction. The spin-flip scattering amplitude depends on the chemical composition of the steps, leading to total confinement for pure Bi step edges, and considerable leakage for mixed Bi-Ag step edges. Additionally, the different localization of the occupied and unoccupied surface bands at Ag and Bi sites leads to a spatial shift of the scattering potential barrier at pure Bi step edges.
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Schirone
authors.affiliation: Departamento de Física de Materiales, Facultad de Ciencias Químicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Apartado 1072, San Sebastián/Donostia, 20080 Basque Country, Spain.|Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, San Sebastián/Donostia, 20018 Basque Country, Spain.|IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
authors.forename: E E
authors.initials: EE
authors.lastname: Krasovskii
authors.affiliation: Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Bihlmayer
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Piquerel
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain.|Instituciò Catalana de Recerca i Estudis Avancats (ICREA), E-08193 Barcelona, Spain.|Department of Materials, ETH Zurich, Hönggerbergring 64, CH-8093 Zurich, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Gambardella
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Mugarza