Field Desorption

Müller, Erwin W.

doi:10.1103/physrev.102.618

Cited by 403 publications

(101 citation statements)

References 20 publications

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“…Contrary to intuition, adatoms travelling toward descending lattice steps can be reflected by a potential-energy barrier, the Ehrlich-Schwoebel (ES) barrier, which prevents them from hopping onto lower layers. Subsequently, using field-ion microscopy [7,8], Ehrlich demonstrated that adatom incorporation at descending steps can also follow a pathway involving push-out and exchange with an island-step atom; that is, the adatom moves downward to replace an edge atom, which is pushed to a position adjacent to the step [9].…”

Section: Introductionmentioning

confidence: 99%

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

et al. 2018

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We carried out density-functional ab initio molecular dynamics (AIMD) simulations of Ti adatom (Ti ad ) migration on, and descent from, square TiN 100 epitaxial islands on TiN(001) at temperatures (T ) ranging from 1200 to 2400 K. Adatom-descent energy barriers determined via ab initio nudged-elastic-band calculations at 0 Kelvin suggest that Ti interlayer transport on TiN(001) occurs essentially exclusively via direct hopping onto a lower layer. However, AIMD simulations reveal comparable rates for Ti ad descent via direct hopping vs push-out/exchange with a Ti island-edge atom for T 1500 K. We demonstrate that this effect is due to surface vibrations, which yield considerably lower activation energies at finite temperatures by significantly modifying the adatom push-out/exchange reaction pathway.

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Section: Introductionmentioning

confidence: 99%

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

et al. 2018

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“…As a final comment, field-assisted evaporation of atoms from a few surface monolayers was first postulated by Müller,42 and studied more recently based on molecular dynamics simulations for a copper nanotip under high electric fields in the 1-100 GV/m range. 43 These are excessively high field values, which are likely not attainable in actual experiments.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Heating based model analysis for explosive emission initiation at metal cathodes

et al. 2015

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This contribution presents a model analysis for the initiation of explosive emission; a phenomena that is observed at cathode surfaces under high current densities. Here, localized heating is quantitatively evaluated on ultrashort time scales as a potential mechanism that initiates explosive emission, based on a two-temperature, relaxation time model. Our calculations demonstrate a strong production of nonequilibrium phonons, ultimately leading to localized melting. Temperatures are predicted to reach the cathode melting point over nanosecond times within the first few monolayers of the protrusion. This result is in keeping with the temporal scales observed experimentally for the initiation of explosive emission. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx

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“…For a tungsten tip at room temperature and approaching the knee voltage, the surface field at the tip of about 500 MV/cm is sufficient to cause tungsten to evaporate. 24 Colder tips have a higher evaporation field 540 MV/cm at 77 K. 25 Thus, for room temperature tungsten tips used to ionize helium, only the first region of the I-V curve is observable without altering the shape of the tip.…”

Section: Introductionmentioning

confidence: 99%

Current-voltage relation for a field ionizing He beam detector

DePonte

Elliott

Kevan

2009

Journal of Applied Physics

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Emerging interest in utilizing the transverse coherence properties of thermal energy atomic and molecular beams motivates the development of ionization detectors with near unit detection efficiency and adequate spatial resolution to resolve interference fringes of submicron dimension. We demonstrate that a field ionization tip coupled to a charged particle detector meets these requirements. We have systematically studied the current-voltage relationship for field ionization of helium using tungsten tips in diffuse gas and in a supersonic helium beam. For all 16 tips used in this study, the dependence of ion current on voltage for tips of fixed radius was found to differ from that for tips held at constant surface electric field. A scaling analysis is presented to explain this difference. Ion current increased on average to the 2.8 power of voltage for a tip at fixed field and approximately fifth power of voltage for fixed radius for a liquid nitrogen cooled tip in room temperature helium gas. For the helium beam, ion current increased as 2.2 power of voltage with constant surface field. The capture region of the tips was found to be up to 0.1 m 2 for diffuse gas and 0.02 m 2 in the beam. Velocity dependence and orientation of tip to beam were also studied.

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Field Desorption

Cited by 403 publications

References 20 publications

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

Heating based model analysis for explosive emission initiation at metal cathodes

Current-voltage relation for a field ionizing He beam detector

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