Plasmonic Nanobilliards: Controlling Nanoparticle Movement Using Forces Induced by Swift Electrons

• Published in: Nano letters Vol. 11; no. 8; pp. 3388 - 3393
• Main Authors: Batson, P. E, Reyes-Coronado, A, Barrera, R. G, Rivacoba, A, Echenique, P. M, Aizpurua, J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.08.2011
• Subjects: Bonding; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Construction; Coupling (molecular); Cross-disciplinary physics: materials science; rheology; Electron beams; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Image charge; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Metal particles; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanostructure; Physics; Plasmonics; Plasmons; Structure of solids and liquids; crystallography; Surface and interface electron states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); aloof electron scattering; Plasmonics; optical forces; plasmon hybridization; plasmonic forces; nanoparticle coalescence; Nanoparticles; Nanometer scale; Electron beams; Symmetry property; Plasmons; Nanostructures; Metal particle; Nanostructured materials
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl201795u

Manipulation of nanoscale objects to build useful structures requires a detailed understanding and control of forces that guide nanoscale motion. We report here observation of electromagnetic forces in groups of nanoscale metal particles, derived from the plasmonic response to the passage of a swift electron beam. At moderate impact parameters, the forces are attractive, toward the electron beam, in agreement with simple image charge arguments. For smaller impact parameters, however, the forces are repulsive, driving the nanoparticle away from the passing electron. Particle pairs are most often pulled together by coupled plasmon modes having bonding symmetry. However, placement of the electron beam between a particle pair pushes the two particles apart by exciting antibonding plasmonic modes. We suggest how the repulsive force could be used to create a nanometer-sized trap for moving and orienting molecular-sized objects.