Kree, Reiner

[["dc.bibliographiccitation.artnumber","193403"],["dc.bibliographiccitation.issue","19"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","65"],["dc.contributor.author","Hartmann, Alexander K."],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Geyer, U."],["dc.contributor.author","Kolbel, M."],["dc.date.accessioned","2018-11-07T10:29:51Z"],["dc.date.available","2018-11-07T10:29:51Z"],["dc.date.issued","2002"],["dc.description.abstract","A simple (2+1)-dimensional discrete model is introduced to study the evolution of solid surface morphologies during ion beam sputtering. The model is based on the same assumptions about the erosion process as the existing analytic theories. Due to its simple structure, simulations of the model can be performed on time scales where effects beyond the linearized theory become important. Whereas for short times we observe the formation of ripple structures in accordance with the linearized theory, we find a roughening surface for intermediate times. The long-time behavior of the model strongly depends on the surface relaxation mechanism."],["dc.identifier.doi","10.1103/PhysRevB.65.193403"],["dc.identifier.isi","000175860900029"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43732"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1550-235X"],["dc.relation.issn","1098-0121"],["dc.title","Long-time effects in a simulation model of sputter erosion"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","125407"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","71"],["dc.contributor.author","Feix, M."],["dc.contributor.author","Hartmann, Alexander K."],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Munoz-Garcia, J."],["dc.contributor.author","Cuerno, R."],["dc.date.accessioned","2018-11-07T11:21:29Z"],["dc.date.available","2018-11-07T11:21:29Z"],["dc.date.issued","2005"],["dc.description.abstract","Theoretical continuum models that describe the formation of patterns on surfaces of targets undergoing ion-beam sputtering are based on Sigmund's formula, which describes the spatial distribution of the energy deposited by the ion. For small angles of incidence and amorphous or polycrystalline materials, this description seems to be suitable, and leads to the classic Bradley and Harper (BH) morphological theory [R. M. Bradley and J. M. E. Harper,, J. Vac. Sci. Technol. A 6, 2390 (1988)]. Here we study the sputtering of Cu crystals by means of numerical simulations under the binary-collision approximation. We observe significant deviations from Sigmund's energy distribution. In particular, the distribution that best fits our simulations has a minimum near the position where the ion penetrates the surface, and the decay of energy deposition with distance to ion trajectory is exponential rather than Gaussian. We provide a modified continuum theory which takes these effects into account and explores the implications of the modified energy distribution for the surface morphology. In marked contrast with BH's theory, the dependence of the sputtering yield with the angle of incidence is nonmonotonous, with a maximum for nongrazing incidence angles."],["dc.identifier.doi","10.1103/PhysRevB.71.125407"],["dc.identifier.isi","000228923300122"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55782"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","American Physical Soc"],["dc.relation.issn","1098-0121"],["dc.title","Influence of collision cascade statistics on pattern formation of ion-sputtered surfaces"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","195405"],["dc.bibliographiccitation.issue","19"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","71"],["dc.contributor.author","Yewande, E. O."],["dc.contributor.author","Hartmann, Alexander K."],["dc.contributor.author","Kree, Reiner"],["dc.date.accessioned","2018-11-07T11:05:48Z"],["dc.date.available","2018-11-07T11:05:48Z"],["dc.date.issued","2005"],["dc.description.abstract","Periodic ripples generated from the off-normal-incidence ion-beam bombardment of solid surfaces have been observed to propagate with a dispersion in the velocity. We investigate this ripple behavior by means of a Monte Carlo model of the erosion process, in conjuction with one of two different surface-diffusion mechanisms, representative of two different classes of materials; one is a Arrhenius-type Monte Carlo method including a term (possibly zero) that accounts for the Schwoebel effect, while the other is a thermodynamic mechanism without the Schwoebel effect. We find that the behavior of the ripple velocity and wavelength depends on the sputtering time scale, which is qualitatively consistent with experiments. Futhermore, we observe a strong temperature dependance of the ripple velocity, calling for experiments at different temperatures. Also, we observe that the ripple velocity vanishes ahead of the periodic ripple pattern."],["dc.identifier.doi","10.1103/PhysRevB.71.195405"],["dc.identifier.isi","000230244100100"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52148"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","American Physical Soc"],["dc.relation.issn","1098-0121"],["dc.title","Propagation of ripples in Monte Carlo models of sputter-induced surface morphology"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","115434"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","73"],["dc.contributor.author","Yewande, E. O."],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Hartmann, Alexander K."],["dc.date.accessioned","2018-11-07T10:15:46Z"],["dc.date.available","2018-11-07T10:15:46Z"],["dc.date.issued","2006"],["dc.description.abstract","We study solid surface morphology created by off-normal ion-beam sputtering with an atomistic solid-on-solid model of sputter erosion. With respect to an earlier version of the model, we extend this model with the inclusion of lateral erosion. Using the two-dimensional structure factor, we found an upper bound mu similar or equal to 2, in the lateral straggle mu, for clear ripple formation. Above this upper bound, for longitudinal straggle sigma greater than or similar to 1.7, we found the possibility of dot formation (without sample rotation). Moreover, a temporal crossover from a hole topography to ripple topography with the same value of collision cascade parameters was found. Finally, a scaling analysis of the roughness, using the consecutive gradient approach, yields the growth exponents beta=0.33 and 0.67 for two different topographic regimes. The results are discussed in the context of the continuum theory."],["dc.identifier.doi","10.1103/PhysRevB.73.115434"],["dc.identifier.isi","000236467300154"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40880"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Morphological regions and oblique-incidence dot formation in a model of surface sputtering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1403"],["dc.bibliographiccitation.issue","8-9"],["dc.bibliographiccitation.journal","NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS"],["dc.bibliographiccitation.lastpage","1406"],["dc.bibliographiccitation.volume","267"],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Yasseri, Taha"],["dc.contributor.author","Hartmann, Alexander K."],["dc.date.accessioned","2018-11-07T08:30:31Z"],["dc.date.available","2018-11-07T08:30:31Z"],["dc.date.issued","2009"],["dc.description.abstract","We present a new Monte Carlo model and a new continuum theory of surface pattern formation due to \"surfactant sputtering\", i.e. erosion by ion beam sputtering including a submonolayer coverage of additional, co-sputtered surfactant atoms. This setup, which has been realized in recent experiments in a controlled way leads to a number of interesting possibilities to modify pattern forming processing conditions. We will present three simple scenarios, which illustrate some potential applications of the method. In all three cases, simple Bradley-Harper type ripples appear in the absence of surfactant, whereas new, interesting structures emerge during surfactant sputtering. (C) 2009 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.nimb.2009.01.150"],["dc.identifier.isi","000266519900048"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16909"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","16th International Conference on Ion Beam Modification of Materials"],["dc.relation.eventlocation","Dresden, GERMANY"],["dc.relation.issn","1872-9584"],["dc.relation.issn","0168-583X"],["dc.title","Surfactant Sputtering: Theory of a new method of surface nanostructuring by ion beams"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","155325"],["dc.bibliographiccitation.issue","15"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","75"],["dc.contributor.author","Yewande, Emmanuel O."],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Hartmann, Alexander K."],["dc.date.accessioned","2018-11-07T11:03:53Z"],["dc.date.available","2018-11-07T11:03:53Z"],["dc.date.issued","2007"],["dc.description.abstract","We implement substrate rotation in a 2+1-dimensional solid-on-solid model of ion-beam sputtering of solid surfaces. With this extension of the model, we study the effect of concurrent rotation, as the surface is sputtered, on possible topographic regions of surface patterns. In particular, we perform a detailed numerical analysis of the time evolution of dots obtained from our Monte Carlo simulations at off-normal-incidence sputter erosion. We found the same power-law scaling exponents of the dot characteristics for two different sets of ion-material combinations, without and with substrate rotation."],["dc.identifier.doi","10.1103/PhysRevB.75.155325"],["dc.identifier.isi","000246075300085"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/51711"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Numerical analysis of quantum dots on off-normal incidence ion sputtered surfaces"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","224015"],["dc.bibliographiccitation.issue","22"],["dc.bibliographiccitation.journal","Journal of Physics Condensed Matter"],["dc.bibliographiccitation.volume","21"],["dc.contributor.author","Hartmann, Alexander K."],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Yasseri, Taha"],["dc.date.accessioned","2018-11-07T08:28:49Z"],["dc.date.available","2018-11-07T08:28:49Z"],["dc.date.issued","2009"],["dc.description.abstract","A class of simple, (2 + 1)-dimensional, discrete models is reviewed, which allow us to study the evolution of surface patterns on solid substrates during ion beam sputtering (IBS). The models are based on the same assumptions about the erosion process as the existing continuum theories. Several distinct physical mechanisms of surface diffusion are added, which allow us to study the interplay of erosion-driven and diffusion-driven pattern formation. We present results from our own work on evolution scenarios of ripple patterns, especially for longer timescales, where nonlinear effects become important. Furthermore we review kinetic phase diagrams, both with and without sample rotation, which depict the systematic dependence of surface patterns on the shape of energy depositing collision cascades after ion impact. Finally, we discuss some results from more recent work on surface diffusion with Ehrlich-Schwoebel barriers as the driving force for pattern formation during IBS and on Monte Carlo simulations of IBS with codeposition of surfactant atoms."],["dc.identifier.doi","10.1088/0953-8984/21/22/224015"],["dc.identifier.isi","000266581000016"],["dc.identifier.pmid","21715753"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16509"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","1361-648X"],["dc.relation.issn","0953-8984"],["dc.title","Simulating discrete models of pattern formation by ion beam sputtering"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1407"],["dc.bibliographiccitation.issue","8-9"],["dc.bibliographiccitation.journal","NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS"],["dc.bibliographiccitation.lastpage","1411"],["dc.bibliographiccitation.volume","267"],["dc.contributor.author","Kree, Reiner"],["dc.contributor.author","Yasseri, Taha"],["dc.contributor.author","Hartmann, Alexander K."],["dc.date.accessioned","2018-11-07T08:30:31Z"],["dc.date.available","2018-11-07T08:30:31Z"],["dc.date.issued","2009"],["dc.description.abstract","We present a continuum theory and a Monte Carlo model of self-organized surface pattern formation by ion-beam sputtering including effects of beam profiles. Recently, it has turned out that such secondary ion-beam parameters may have a strong influence on the types of emerging patterns. We first discuss several cases, for which beam profiles lead to random parameters in the theory of pattern formation. Subsequently we study the evolution of the averaged height profile in continuum theory and find that the typical Bradley-Harper scenario of dependence of ripple patterns on the angle of incidence can be changed qualitatively. Beam profiles are implemented in Monte Carlo simulations, where we find generic effects on pattern formation. Finally, we demonstrate that realistic beam profiles, taken from experiments, may lead to qualitative changes of surface patterns. (C) 2009 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.nimb.2009.01.064"],["dc.identifier.isi","000266519900049"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16910"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","16th International Conference on Ion Beam Modification of Materials"],["dc.relation.eventlocation","Dresden, GERMANY"],["dc.relation.issn","0168-583X"],["dc.title","The influence of beam divergence on ion-beam induced surface patterns"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]