Image potential in scanning transmission electron microscopy

Rivacoba, A.; Zabala, Nerea; Aizpurua, Javier

doi:10.1016/s0079-6816(00)00005-8

Cited by 67 publications

(74 citation statements)

References 147 publications

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“…The total momentum transfer P ជ from a fast electron to a particle in vacuum can be calculated by adding the contributions to the force produced on the particle along the electron trajectory, 26 or equivalently integrating over time the instantaneous force F ជ mec ͑t͒. Considering the equation for the conservation of momentum 27 and integrating it over time, the total momentum transfer P ជ is given by…”

Section: Theorymentioning

confidence: 99%

Electromagnetic forces on plasmonic nanoparticles induced by fast electron beams

et al. 2010

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The total momentum transfer from fast electron beams, like those employed in scanning transmission electron microscopy ͑STEM͒, to plasmonic nanoparticles is calculated. The momentum transfer is obtained by integrating the electromagnetic forces acting on the particles over time. Numerical results for single and dimer metallic nanoparticles are presented, for sizes ranging between 2 and 80 nm. We analyze the momentum transfer in the case of metallic dimers where the different relevant parameters such as particle size, interparticle distance, and electron beam impact parameter are modified. It is shown that depending on the specific values of the parameters, the total momentum transfer yields a force that can be either attractive or repulsive. The time-average forces calculated for electron beams commonly employed in STEM are on the order of piconewtons, comparable in magnitude to optical forces and are thus capable of producing movement in the nanoparticles. This effect can be exploited in mechanical control of nanoparticle induced motion.

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Section: Theorymentioning

confidence: 99%

Electromagnetic forces on plasmonic nanoparticles induced by fast electron beams

et al. 2010

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“…Typical examples are intra-atomic d-d excitations in strongly correlated transition-metal oxides [17][18][19] or longitudinal p-like excitons in sp cubic crystals. 2,3,9 In addition, the new electron microscopes are able today to reach very high spatial resolution (well under 1 nm) for the loss spectroscopy, [20][21][22] which, in order to be investigated from the theoretical point of view, requires the knowledge of the dielectric function not at just q = 0, but at many q's, in order to Fourier transform back in real space. Concerning theory, however, ab initio simulations lie a long way behind experiments.…”

Section: Introductionmentioning

confidence: 99%

Exciton dispersion from first principles

Gatti

Sottile

2013

Phys. Rev. B

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We present a scheme to calculate exciton dispersions in real materials that is based on the first-principles many-body Bethe-Salpeter equation. We assess its high level of accuracy by comparing our results for LiF with recent inelastic x-ray scattering experimental data on a wide range of energy and momentum transfer. We show its great analysis power by investigating the role of the different electron-hole interactions that determine the exciton band structure and the peculiar "exciton revival" at large momentum transfer. Our calculations for solid argon are a prediction and a suggestion for future experiments. These results demonstrate that the first-principles Bethe-Salpeter equation is able to describe the dispersion of localized and delocalized excitons on equal footing and represent a key step for the ab initio study of the exciton mobility.

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“…In this context, EELS has been recently demonstrated to image plasmon modes with spatial resolution better than a hundredth of the wavelength in triangular nanoprisms [3]. However, despite significant progress from the theoretical side [10], no synthetic and universal picture has emerged to explain the spatial modulation of EELS measurements on arbitrary nanostructures.In this Letter, we show that EELS provides direct information on the photonic local density of states (LDOS), and thus it constitutes a suitable tool for truly nanometric characterization of photonic nanostructures. A rigorous derivation of this statement is offered, illustrated by numerical examples for both translationally invariant geometries and planar structures.…”

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confidence: 99%

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confidence: 99%

Probing the Photonic Local Density of States with Electron Energy Loss Spectroscopy

2008

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Electron energy loss spectroscopy performed in transmission electron microscopes is shown to directly render the photonic local density of states with unprecedented spatial resolution, currently below the nanometer. Two special cases are discussed in detail: (i) 2D photonic structures with the electrons moving along the translational axis of symmetry and (ii) quasiplanar plasmonic structures under normal incidence. Nanophotonics in general and plasmonics, in particular, should benefit from these results connecting the unmatched spatial resolution of electron energy loss spectroscopy with its ability to probe basic optical properties such as the photonic local density of states. DOI: 10.1103/PhysRevLett.100.106804 PACS numbers: 73.20.Mf, 78.20.Bh, 79.20.Uv While a plethora of nanophotonic structures is currently being devised for diverse applications like achieving single molecule sensitivity in biosensing [1] or molding the flow of light over nanoscale distances for signal processing [2], no optical characterization technique exists that can render spectroscopic details with truly nanometer spatial resolution. The need for that kind of technique is particularly acute in nanometric plasmonic designs that benefit from sharp edges and metallic surfaces in close proximity to yield large enhancements of the electromagnetic field.Scanning transmission electron microscopes (STEM) can plausibly cover this gap, as they perform electron energy loss spectroscopy (EELS) with increasingly improved energy resolution that is quickly approaching the width of plasmon excitations in noble metals [3] and with spatial resolution well below the nanometer [4]. The connection between EELS and photonics can be readily established when low-energy losses in the sub-eV to a few eV range are considered, compatible with typical photon energies in photonic devices. A formidable amount of information is available in the literature for this so-called valence EELS, including for instance studies of single nanoparticles of various shapes [3,5], interacting nanoparticles [6], thin films [7], composite metamaterials [8], and carbon nanostructures [9]. Many of these reports are relevant to current nanophotonics research, in which the optical response of nanoparticles, nanoparticle assemblies, and patterned nanostructures plays a central role. In this context, EELS has been recently demonstrated to image plasmon modes with spatial resolution better than a hundredth of the wavelength in triangular nanoprisms [3]. However, despite significant progress from the theoretical side [10], no synthetic and universal picture has emerged to explain the spatial modulation of EELS measurements on arbitrary nanostructures.In this Letter, we show that EELS provides direct information on the photonic local density of states (LDOS), and thus it constitutes a suitable tool for truly nanometric characterization of photonic nanostructures. A rigorous derivation of this statement is offered, illustrated by numerical examples for both translationally invariant geomet...

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Image potential in scanning transmission electron microscopy

Cited by 67 publications

References 147 publications

Electromagnetic forces on plasmonic nanoparticles induced by fast electron beams

Electromagnetic forces on plasmonic nanoparticles induced by fast electron beams

Exciton dispersion from first principles

Probing the Photonic Local Density of States with Electron Energy Loss Spectroscopy

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