title: Elastic and inelastic electrons in the double-slit experiment: A variant of Feynman's which-way set-up.
abstract: Modern nanotechnology tools allowed us to prepare slits of 90 nm width and 450 nm spacing in a screen almost completely opaque to 200 keV electrons. Then by covering both slits with a layer of amorphous material and carrying out the experiment in a conventional transmission electron microscope equipped with an energy filter we can demonstrate that the diffraction pattern, taken by selecting the elastically scattered electrons, shows the presence of interference fringes, but with a bimodal envelope which can be accounted for by taking into account the non-constant thickness of the deposited layer. However, the intensity of the inelastically scattered electrons in the diffraction plane is very broad and at the limit of detectability. Therefore the experiment was repeated using an aluminum film and a microscope also equipped with a Schottky field emission gun. It was thus possible to observe also the image due to the inelastically scattered electron, which does not show interference phenomena both in the Fraunhofer or Fresnel regimes. If we assume that inelastic scattering through the thin layer covering the slits provides the dissipative process of interaction responsible for the localization mechanism, then these experiments can be considered a variant of the Feynman which-way thought experiment.
authors: Department FIM, University of Modena and Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy; CNR-Institute of Nanoscience-S3, Via G. Campi 213/a, 41125 Modena, Italy.
authors: Stefano
authors: S
authors: Frabboni
authors: CNR-Institute of Nanoscience-S3, Via G. Campi 213/a, 41125 Modena, Italy.
authors: Gian Carlo
authors: GC
authors: Gazzadi
authors: CNR-Institute of Nanoscience-S3, Via G. Campi 213/a, 41125 Modena, Italy; CNR-IMEM, Parco delle Scienze 37a, 43100 Parma, Italy.
authors: Vincenzo
authors: V
authors: Grillo
authors: Department of Physics and Astronomy, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna, Italy.
authors: Giulio
authors: G
authors: Pozzi
keywords: Foundations of quantum mechanics; Matter waves; Measurement theory; Nanolithography; Transmission electron microscopy