References of "Rosandi, Yudi"
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See detailSputtering at grazing ion incidence: Influence of adatom islands
Rosandi, Yudi; Redinger, Alex UL; Michely, Thomas et al

in PHYSICAL REVIEW B (2010), 82(12),

When energetic ions impinge at grazing incidence onto an atomically flat terrace, they will not sputter. However, when adatom islands (containing N atoms) are deposited on the surface, they induce ... [more ▼]

When energetic ions impinge at grazing incidence onto an atomically flat terrace, they will not sputter. However, when adatom islands (containing N atoms) are deposited on the surface, they induce sputtering. We investigate this effect for the specific case of 83 degrees-incident 5 keV Ar ions on a Pt (111) surface by means of molecular-dynamics simulation and experiment. We find that-for constant coverage Theta-the sputter yield has a maximum at island sizes of N congruent to 10-20. A detailed picture explaining the decline of the sputter yield toward larger and smaller island sizes is worked out. Our simulation results are compared with dedicated sputtering experiments, in which a coverage 0.09 of Pt adatoms are deposited onto the Pt (111) surface and form islands with a broad distribution around a most probable size of N congruent to 20. [less ▲]

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See detailInfluence of a single adatom on sputtering at grazing incidence - A molecular-dynamics case study of 5 keV Ar impact on Pt (111)
Rosandi, Yudi; Redinger, Alex UL; Michely, Thomas et al

in SURFACE SCIENCE (2009), 603(2), 320-325

Grazing incidence ion impact on a flat terrace lets the projectile reflect specularly off the surface, leading to little or no damage production or sputtering. The presence of isolated surface defects may ... [more ▼]

Grazing incidence ion impact on a flat terrace lets the projectile reflect specularly off the surface, leading to little or no damage production or sputtering. The presence of isolated surface defects may change this behaviour drastically. We investigate this phenomenon for the specific case of 5 keV Ar ions impinging at 83 degrees towards the surface normal onto the Pt (111) surface. Molecular-dynamics simulations allow to study the influence of isolated adatoms in detail. The scattering of the projectile from the adatom can redirect the projectile, or let the adatom recoil, such that either of them deposits considerable energy in the target surface, leading to abundant damage production and sputtering. Two distinct collision zones are identified: (i) When the projectile hits the surface in front of the adatom, it may collide with the adatom indirectly (after being specularly reflected off the surface); (ii) alternatively, it may hit the adatom directly. We quantify our results by measuring the zone of influence (congruent to 13 angstrom(2)) around the adatom, into which the projectile must hit in order to collide with the adatom, and by the sputter cross section of roughly 110 angstrom(2). The data compare well with previous simulation results of sputtering from an atomically rough surface. (C) 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailCompetition of terrace and step-edge sputtering under oblique-incidence ion impact on a stepped Pt(111) surface
Rosandi, Yudi; Redinger, Alex UL; Michely, Thomas et al

in NUCLEAR INSTRUMENTS METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS (2009), 267(16), 2769-2773

Using molecular-dynamics simulation, we study the sputtering of a Pt(111) surface under oblique and glancing incidence 5 keV Ar ions. For incidence angles larger than a critical angle theta(c), the ... [more ▼]

Using molecular-dynamics simulation, we study the sputtering of a Pt(111) surface under oblique and glancing incidence 5 keV Ar ions. For incidence angles larger than a critical angle theta(c), the projectile is reflected off the surface and the sputter yield is zero. We discuss the azimuth dependence of the critical angle theta(c) with the help of the surface corrugation felt by the impinging ion. If a step exists on the surface, sputtering occurs also for glancing incidence theta > theta(c). We demonstrate that for realistic step densities, the total sputtering of a stepped surface may be sizable even at glancing incidence. (C) 2009 Elsevier B.V. All rights reserved. [less ▲]

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See detailStep-edge sputtering through grazing incidence ions investigated by scanning tunneling microscopy and molecular dynamics simulations
Redinger, Alex UL; Rosandi, Yudi; Urbassek, Herbert M. et al

in PHYSICAL REVIEW B (2008), 77(19),

Scanning tunneling microscopy is used to quantify step-edge sputtering of Pt(111) at 550 K by grazing incidence ion bombardment with 5 keV Ar(+) ions. For bombardment conditions causing negligible erosion ... [more ▼]

Scanning tunneling microscopy is used to quantify step-edge sputtering of Pt(111) at 550 K by grazing incidence ion bombardment with 5 keV Ar(+) ions. For bombardment conditions causing negligible erosion on terraces, damage features associated with step bombardment allow us to visualize step retraction and thus to quantify the step-edge sputtering yield. An alternative method for step-edge yield determination, which is applicable under more general conditions, is the analysis of the concentration of ascending steps together with the removed amount as a function of ion fluence. Interestingly, the azimuthal direction of the impinging ions with respect to the surface significantly changes the sputtering yield at step edges. This change is attributed to the orientation dependence of subsurface channeling. Atomistic insight into step-edge sputtering and its azimuthal dependence is given by molecular dynamics simulations of ion impacts at 0 and 550 K. The simulations also demonstrate a strong dependence of the step-edge sputtering yield on temperature. [less ▲]

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See detailMechanisms of pattern formation in grazing-incidence ion bombardment of Pt(111)
Hansen, Henri; Redinger, Alex UL; Messlinger, Sebastian et al

in PHYSICAL REVIEW B (2006), 73(23),

Ripple patterns forming on Pt(111) due to 5 keV Ar(+) grazing-incidence ion bombardment were investigated by scanning tunneling microscopy in a broad temperature range from 100 to 720 K and for ion ... [more ▼]

Ripple patterns forming on Pt(111) due to 5 keV Ar(+) grazing-incidence ion bombardment were investigated by scanning tunneling microscopy in a broad temperature range from 100 to 720 K and for ion fluences up to 3x10(20) ions/m(2). A detailed morphological analysis together with molecular dynamics simulations of single ion impacts allow us to develop atomic scale models for the formation of these patterns. The large difference in step edge versus terrace damage is shown to be crucial for ripple formation under grazing incidence. The importance of distinct diffusion processes-step adatom generation at kinks and adatom lattice gas formation-for temperature dependent transitions in the surface morphology is highlighted. Surprisingly, ion bombardment effects like thermal spike induced adatom production and planar subsurface channeling are important for pattern ordering. [less ▲]

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