Diffusion and nucleation of yttrium atoms on Si(111)7×7: A growth model

Polop, C.; Vasco, E.; Martin-Gago, J.A.; Sacedón, J. L.

doi:10.1103/physrevb.66.085324

Cited by 35 publications

(22 citation statements)

References 30 publications

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“…Usually, the diffusion of atoms on low-index surfaces is two dimensional and rather isotropic, like in the case of various adsorbates on the Si(111) surface [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. However, the movement of atoms can become strongly anisotropic or even quasi-one-dimensional in the presence of a specific surface reconstruction or on stepped (vicinal) templates [23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Surface diffusion of Pb atoms on the Si(553)-Au surface in narrow quasi-one-dimensional channels

et al. 2014

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The one-dimensional diffusion of individual Pb atoms on the Si(553)-Au surface has been investigated by a combination of scanning tunneling microscopy (STM), spectroscopy (STS), and first-principles density functional theory. The obtained results unambiguously prove that the diffusion channels are limited to a narrow region between Au chains and step edges of the surface. Much wider channels observed in STM and STS data have electronic origin and result from an interaction of Pb with surface atoms. The length of the channels is determined by a distance between defects at step edges of the Si(553)-Au surface. The defects can act as potential barriers or potential wells for Pb atoms, depending on their origin.

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Section: Introductionmentioning

confidence: 99%

Surface diffusion of Pb atoms on the Si(553)-Au surface in narrow quasi-one-dimensional channels

et al. 2014

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“…[9][10][11] These experiments revealed the high mobility at RT of single Pb adatoms within the half-unit cells where they are almost trapped, presenting features that have been found afterwards for other adsorbates such as Tl, Si, Sn, Ag, and Y. 1,[12][13][14][15] No previous knowledge existed, however, either on the stable adsorption sites or on the diffusion processes inside the (7ϫ7) half cells, issues which are directly addressed in the present work.…”

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confidence: 98%

Single adatom adsorption and diffusion onSi(111)−(7×7)surfaces: Scanning tunneling microscopy and first-principles calculations

et al. 2003

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The adsorption and diffusion of single Pb atoms on Si(111)-(7ϫ7) surfaces have been studied by scanning tunneling microscopy ͑STM͒ and first-principles density functional calculations. STM experiments at temperatures from 100 to 130 K have revealed three regions of preferential adsorption, inside each half-unit cell, as well as real time diffusion events between them. The stable adsorption sites have been determined by firstprinciples calculations and by comparing simulated and measured STM images. The activation barriers for the motion inside the half-unit cells have been calculated and measured experimentally. A very good agreement between calculations and experiments has been found.Detailed atomic-scale knowledge of adsorption and diffusion mechanisms of single adatoms on highly reconstructed semiconductor surfaces is of fundamental importance for many present and future technological processes. In particular, recent works have unveiled the potentiality, for next generation devices, of self-organized nanoclusters on Si(111)-(7ϫ7). 1-3 However, there is still a lack of both theoretical and experimental information on the stable adsorption sites, diffusion pathways, and energy barriers which are crucial to understand the formation of such nanoclusters.In the last few years, scanning tunneling microscopy ͑STM͒ has become the technique of choice to measure surface diffusion at the atomic scale, nicely complementing the wealth of data from field ion microscopy. 4 STM experiments interpretation, however, generally requires theoretical calculations, ideally from first principles. Such calculations remain a formidable task for highly reconstructed surfaces. The first density-functional theory ͑DFT͒ calculations of the Si(111)-(7ϫ7) surface were a landmark in massive parallel computation. 5,6 Further algorithm and hardware improvements have allowed to study this surface with high accuracy. 7 First-principles calculations involving adsorbate adsorption on this surface are, however, still scarce, and even scarcer if including diffusion barriers and pathways ͓to our knowledge, there is only a very recent report 8 on the analysis of diffusion of Si adatoms on Si(111)-(7ϫ7) surfaces, which appeared after the submission of this study͔.In the present work, we have performed combined variable-temperature STM experiments and DFT firstprinciples calculations of the adsorption and diffusion of single Pb adatoms on Si(111)-(7ϫ7). The motivation for this system was double: on one hand, it is a prototype for a nonreactive interface; on the other hand, there is already some information on it from STM at room temperature ͑RT͒. 9-11 These experiments revealed the high mobility at RT of single Pb adatoms within the half-unit cells where they are almost trapped, presenting features that have been found afterwards for other adsorbates such as Tl, Si, Sn, Ag, and Y. 1,12-15 No previous knowledge existed, however, either on the stable adsorption sites or on the diffusion processes inside the (7ϫ7) half cells, issues which are directly addre...

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“…The Si(1 1 1)7 · 7 surface acts as a stable template, which periodic potential wells trap the adsorbate atoms and, as a result, the clusters comprising a fixed number of atoms are formed [1,2]. Numerous investigations have demonstrated that many metals (e.g., Tl [3], In [4,5], Pb [6], Ag [7][8][9], Sn [4], Y [10], Cr [11]) when being deposited onto the Si(1 1 1)7 · 7 surface held at modest temperatures close to the room temperature (RT), demonstrate a clear tendency for ordered magic nanoclustering. In these cases, the forming nanocluster arrays are characterized by a perfect spatial ordering in the 7 · 7 lattice with preferential occupation of the faulted halves of the 7 · 7 unit cells (HUCs), but the clusters themselves are not so perfect: they do not display a well-defined shape; there is also a certain variation in the number of atoms constituting each cluster.…”

Section: Introductionmentioning

confidence: 99%