Multiple-cascade model for the filling of hollow Ne atoms moving below an Al surface

Stolterfoht, N.; Arnau, A.; Grether, M.; Köhrbrück, R.; Spieler, A.; Page, Ryan; Saal, Amar; Thomaschewski, Jörg; Bleck-Neuhaus, Jörn

doi:10.1103/physreva.52.445

Cited by 90 publications

(26 citation statements)

References 48 publications

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“…Together with the explosion time scales determined in this work, a number of atomic physics and materials time scales must also be considered in order to predict what conditions need to be achieved in the laboratory in order to produce the Coulomb explosion. [56][57][58][59][60]43,36 This will be the topic of a more Panel ͑a͒ is for the 365-ion system and panel ͑b͒ the 265-ion system. Notice that after the initial shock, which ends at 80-100 fs, most of the energy originally stored in the ions is transferred to the substrate.…”

Section: Discussionmentioning

confidence: 99%

Nanoscale modification of silicon surfaces via Coulomb explosion

Cheng

Gillaspy

1997

Phys. Rev. B

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Coulomb explosions on silicon surfaces are studied using large-scale molecular-dynamics simulations. Processes under investigation begin by embedding a region consisting of 265-365 singly charged Si ϩ ions on a Si ͓111͔ surface. The repulsive electrostatic energy, initially stored in the charged region, leads to a local state with ultrahigh pressure and stress. During the relaxation process, part of the potential energy propagates into the surrounding region while the remainder is converted to kinetic energy, resulting in a Coulomb explosion. Within less than 1.0 ps, a nanometer-sized hole on the surface is formed. A full analysis of the density, temperature, pressure, and energy distribution as functions of time reveals the time evolution of physical properties of the systems related to the violent explosive event. A shock wave that propagates in the substrate is formed during the first stage of the explosion, 0ϽtϽ100 fs. The speed of the shock wave is twice the average speed of sound. After the initial shock the extreme nonequilibrium conditions leads to ultrarapid evaporation of Si atoms from the surface. Qualitatively similar features are observed on a smaller scale when the number of initial surface charges is reduced to 100. Our simulations demonstrate the details of a process that can lead to permanent structure on a semiconductor surface at the nanoscale level. The work reported here provides physical insights for experimental investigations of the effects of slow, highly charged ions (Q Ͼ40, e.g.͒ on semiconductor materials.

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Section: Discussionmentioning

confidence: 99%

Nanoscale modification of silicon surfaces via Coulomb explosion

Cheng

Gillaspy

1997

Phys. Rev. B

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“…electron side-feeding into energetically lower ion states occurs at small impact parameters. Hence this leads to a fast neutralization of the ion [11][12][13][14] leaving the target surface locally with a large density of electronic excitations similar to the case of electron irradiation. Depending on charge carrier mobilities and densities, holes, plasmons and other types of excitations may be screened rapidly or are mobile enough to dissipate the energy over a larger volume within a few fs.…”

Section: Energy Deposition Of Slow Highly Charged Ionsmentioning

confidence: 95%

Highly charged ion induced nanostructures at surfaces by strong electronic excitations

Wilhelm¹,

El-Said²,

Heller³

et al. 2015

Progress in Surface Science

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a b s t r a c tNanostructure formation by single slow highly charged ion impacts can be associated with high density of electronic excitations at the impact points of the ions. Experimental results show that depending on the target material these electronic excitations may lead to very large desorption yields in the order of a few 1000 atoms per ion or the formation of nanohillocks at the impact site. Even in ultra-thin insulating membranes the formation of nanometer sized pores is observed after ion impact. In this paper, we show recent results on nanostructure formation by highly charged ions and compare them to structures and defects observed after intense electron and light ion irradiation of ionic crystals and graphene. Additional data on energy loss, charge exchange and secondary electron emission of highly charged ions clearly show that the ion charge dominates the defect formation at the surface.

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“…In order to obtain detailed understanding of the exotic hollow atom, the x-ray spectra [9][10][11][12][13][14][15][16][17][18][19][20][21] and the Auger electron spectra [22][23][24][25][26][27][28][29] during its formation and decaying have been investigated intensively over the past 20 years by several groups. Up to now reasonable agreement has been obtained regarding the formation of hollow atoms in the HCI surface interaction [30,31].…”

Section: Introductionmentioning

confidence: 99%

“…Above the surface, electrons in highly excited states deexcite mainly through higher-rate multistep Auger [28,29] and lower-rate x-ray emission processes [1,[13][14][15][16], Since the Auger processes take many steps, thus a long time to decay to the inner shells, and the x-ray transition rate is roughly scaled with the square of energy difference between initial and final states A £ 2, it is possible to observe "above the surface" x-ray emission decaying directly from Rydberg states to the innermost shells. Such x rays are the fingerprints of the highly excited Rydberg atoms or ions.…”

Section: Introductionmentioning

confidence: 99%

Rydberg-to-M-shell x-ray emission of hollowXeq+ (q=27–30)atoms or ions above metallic surfaces

et al. 2015

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X rays originating from transitions from high Rydberg states to the M shell (here called Rydberg-to-M-shell x rays) have been measured in the interaction of Xe1 ' 1 (q = 27-30) ions with aluminum, molybdenum, and beryllium surfaces in the energy range of 350-600 keV, by using a Si(Li) detector. The transition energy calculation by Cowan's program with relativistic correlation indicates that such x rays are mainly from the transition of the higher quantum states, with the principal quantum number from 6 up to 30, directly to M shell of xenon. The yield of the x ray per vacancy in M shell decreases slightly with increasing the projectile energies and is inversely proportional to the work functions of metallic surfaces used. However, it increases rapidly with the increase of the projectile charge states. All of these experimental facts combined with the transition rate calculations indicate that the measured Rydberg-to-M-shell x rays come from the "above the surface" hollow Xe atoms or ions deexcitation, when the inner shells such as N and O have not been filled.

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Multiple-cascade model for the filling of hollow Ne atoms moving below an Al surface

Cited by 90 publications

References 48 publications

Nanoscale modification of silicon surfaces via Coulomb explosion

Nanoscale modification of silicon surfaces via Coulomb explosion

Highly charged ion induced nanostructures at surfaces by strong electronic excitations

Rydberg-to-M-shell x-ray emission of hollowXeq+ (q=27–30)atoms or ions above metallic surfaces

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