On the electron vortex beam wavefunction within a crystal

Mendis, B.G.

doi:10.1016/j.ultramic.2015.05.004

Cited by 9 publications

(6 citation statements)

References 15 publications

(26 reference statements)

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“…When electron vortex beams interact with matter, the cylindrical symmetry is typically broken, and the beam evolves in a highly nontrivial way through the material. In this process, the electron OAM changes significantly for all but the thinnest sample and can even change its sign for certain thickness [238,239,240]. This process can be effectively simulated using standard multislice numerical calculations solving the nonrelativistic Schrödinger equation for a fast electron wavepacket travelling through the potential produced by the atoms.…”

Section: Elastic Interaction Of Vortex Electrons With Mattermentioning

confidence: 99%

Theory and applications of free-electron vortex states

Bliokh¹,

Иванов²,

Guzzinati³

et al. 2017

Physics Reports

302

347

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Both classical and quantum waves can form vortices: with helical phase fronts and azimuthal current densities. These features determine the intrinsic orbital angular momentum carried by localized vortex states. In the past 25 years, optical vortex beams have become an inherent part of modern optics, with many remarkable achievements and applications. In the past decade, it has been realized and demonstrated that such vortex beams or wavepackets can also appear in free electron waves, in particular, in electron microscopy. Interest in free-electron vortex states quickly spread over different areas of physics: from basic aspects of quantum mechanics, via applications for fine probing of matter (including individual atoms), to high-energy particle collision and radiation processes. Here we provide a comprehensive review of theoretical and experimental studies in this emerging field of research. We describe the main properties of electron vortex states, experimental achievements and possible applications within transmission electron microscopy, as well as the possible role of vortex electrons in relativistic and high-energy processes. We aim to provide a balanced description including a pedagogical introduction, solid theoretical basis, and a wide range of practical details. Special attention is paid to translate theoretical insights into suggestions for future experiments, in electron microscopy and beyond, in any situation where free electrons occur.

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Section: Elastic Interaction Of Vortex Electrons With Mattermentioning

confidence: 99%

Theory and applications of free-electron vortex states

Bliokh¹,

Иванов²,

Guzzinati³

et al. 2017

Physics Reports

302

347

View full text Add to dashboard Cite

show abstract

“…3 . Previous studies using the Bloch waves method explored the elastic dynamic scattering of electron vortex beams in crystals 57 , 58 . Such studies showed that with higher semi-convergence angle (30 mrad, m = +1), a vortex beam remains strongly localized with in few (<10) nanometers.…”

Section: Resultsmentioning

confidence: 99%

Probing the localization of magnetic dichroism by atomic-size astigmatic and vortex electron beams

Negi

Idrobo

Rusz

2018

Sci Rep

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We report localization of a magnetic dichroic signal on atomic columns in electron magnetic circular dichroism (EMCD), probed by beam distorted by four-fold astigmatism and electron vortex beam. With astigmatic probe, magnetic signal to noise ratio can be enhanced by blocking the intensity from the central part of probe. However, the simulations show that for atomic resolution magnetic measurements, vortex beam is a more effective probe, with much higher magnetic signal to noise ratio. For all considered beam shapes, the optimal SNR constrains the signal detection at low collection angles of approximately 6–8 mrad. Irrespective of the material thickness, the magnetic signal remains strongly localized within the probed atomic column with vortex beam, whereas for astigmatic probes, the magnetic signal originates mostly from the nearest neighbor atomic columns. Due to excellent signal localization at probing individual atomic columns, vortex beams are predicted to be a strong candidate for studying the crystal site specific magnetic properties, magnetic properties at interfaces, or magnetism arising from individual atomic impurities.

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“…Landau) beams in a uniform magnetic field in the zdirection, as well as Bessel beams, but not LG beams, which are approximate solutions to the paraxial Schrödinger equation [40]. These results however assume uniform electrostatic potential, and do not always hold in a crystal [42][43][44], so that our analysis is only applicable for weakly diffracting specimens. Integration along the electron trajectory with the assumption of a depth independent electron density leads to the quantisation condition 𝑞 𝑧 = 𝜔/2𝜋𝑣.…”

Section: Magnetic Energy Loss For a Vortex Electron Beam With Orbital...mentioning

confidence: 94%

“…𝑛 𝑣 (−𝐑, z) = 𝑛 𝑣 (𝐑, 𝑧); even parity of the electron density also implies that 𝑛 ̃𝑣(𝐪 ⊥ , 𝑧) is a real quantity. For a vortex beam in a crystalline specimen however this simple relationship breaks down due to dynamic diffraction [42][43][44].…”

Section: Magnetic Energy Loss For a Vortex Electron Beam With Orbital...mentioning

confidence: 99%

On the electron vortex beam wavefunction within a crystal

Cited by 9 publications

References 15 publications

Theory and applications of free-electron vortex states

Theory and applications of free-electron vortex states

Probing the localization of magnetic dichroism by atomic-size astigmatic and vortex electron beams

A semi-classical theory of magnetic inelastic scattering in transmission electron energy loss spectroscopy

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