Dynamic scaling of the island-size distribution and percolation in a model of submonolayer molecular-beam epitaxy

Amar, Jacques G.; Family, Fereydoon; Lam, Pui-Man

doi:10.1103/physrevb.50.8781

Cited by 331 publications

(247 citation statements)

References 45 publications

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“…In this case, island percolation occurs at a coverage of ⌰ Ϸ 0.9 ML. 34 In other words, for coverages below this value the film can be seen as an ensemble of monolayer-high magnetically independent particles, while for coverages above the film becomes a continuously connected structure. Because in ultrathin films with out-of-plane easy axis the critical singledomain diameter is on the order of 1 m ͑Refs.…”

Section: Granular Films: Magnetization Curves and Magnetic Anisotrmentioning

confidence: 99%

High magnetic moments and anisotropies forFexCo1−xmonolayers on Pt(111)

et al. 2008

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The magnetism of 1-ML-thick films of Fe x Co 1−x on Pt͑111͒ was investigated both experimentally, by x-ray magnetic circular dichroism and magneto-optical Kerr effect measurements, and theoretically, by firstprinciples electronic structure calculations, as a function of the film chemical composition. The calculated Fe and Co spin moments are only weakly dependent on the composition and close to 3 B / atom and 2 B / atom, respectively. This trend is also seen in the experimental data, except for pure Fe, where an effective spin moment of only S eff = ͑1.2Ϯ 0.2͒ B / atom was measured. On the other hand, both the orbital moment and the magnetic anisotropy energy show a strong composition dependence with maxima close to the Fe 0.5 Co 0.5 stoichiometry. The experiment, in agreement with theory, gives a maximum magnetic anisotropy energy of 0.5 meV/atom, which is more than 2 orders of magnitude larger than the value observed in bulk bcc FeCo and close to that observed for the L1 0 phase of FePt. The calculations clearly demonstrate that this composition dependence is the result of a fine tuning in the occupation number of the d x 2 −y 2 and d xy orbitals due to the Fe-Co electronic hybridization.

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Section: Granular Films: Magnetization Curves and Magnetic Anisotrmentioning

confidence: 99%

High magnetic moments and anisotropies forFexCo1−xmonolayers on Pt(111)

et al. 2008

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“…The surface area covered by CdTe islands, i.e., the surface coverage, follows a power law relation, which has been already reported for systems subjected to a diffusion-mediated nucleation and growth mechanism. 18 Careful observation of Figs. 2͑c͒ and 2͑d͒, where the islands are large enough, shows that the islands have a triangular shape, a clear indication of a ͓111͔ axial orientation, as will be confirmed later.…”

Section: Resultsmentioning

confidence: 99%

Evolution of crystalline domain size and epitaxial orientation of CdTe/Si(111) quantum dots

Suela

Ribeiro

Ferreira

et al. 2010

Journal of Applied Physics

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We have investigated the crystalline configuration of CdTe quantum dots ͑QDs͒ grown on hydrogen passivated Si͑111͒ substrates by hot wall epitaxy. Coplanar and grazing incidence diffraction were used for determination of dot strain state and the vertical and lateral dimensions of the crystalline domain. A change in aspect ratio was observed as a function of dot size. X-ray diffraction ͑XRD͒ results show that despite a mismatch of almost 20% the islands grow with a fairly good epitaxial orientation with respect to the Si͑111͒ substrate. The dot mosaicity was also determined and was found to decrease with island size from 7°to about 4°for the samples studied, indicating an improvement in epitaxial quality even before the island coalescence. Careful observation of CdTe͑220͒ reflections in an azimuthal scan showed that an additional ensemble of islands is responsible for low-intensity peaks with a 30°symmetry besides the expected 60°symmetry. Transmission electron microscopy results have shown good accordance with atomic force microscopy and XRD and revealed the presence of an amorphous Tellurium rich oxide layer at the CdTe/Si interface, which could explain the fully unstrained QD state observed.

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“…If the average 2D island linear size s av ∼ t z is taken as the characteristic length of the system, it can be deduced that the scaling law for the island size distribution n(s, θ) of 2D epitaxial islands should have the form [111,112] …”

Section: Scaling Invariance Ansatzmentioning

confidence: 99%

Self-assembly of InAs quantum dots on GaAs(001) by molecular beam epitaxy

Jin

2015

Front. Phys.

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Currently, the nature of self-assembly of three-dimensional epitaxial islands or quantum dots (QDs) in a lattice-mismatched heteroepitaxial growth system, such as InAs/GaAs(001) and Ge/Si(001) as fabricated by molecular beam epitaxy (MBE), is still puzzling. The purpose of this article is to discuss how the self-assembly of InAs QDs in MBE InAs/GaAs(001) should be properly understood in atomic scale. First, the conventional kinetic theories that have traditionally been used to interpret QD self-assembly in heteroepitaxial growth with a significant lattice mismatch are reviewed briefly by examining the literature of the past two decades. Second, based on their own experimental data, the authors point out that InAs QD self-assembly can proceed in distinctly different kinetic ways depending on the growth conditions and so cannot be framed within a universal kinetic theory, and, furthermore, that the process may be transient, or the time required for a QD to grow to maturity may be significantly short, which is obviously inconsistent with conventional kinetic theories. Third, the authors point out that, in all of these conventional theories, two well-established experimental observations have been overlooked: i) A large number of “floating” indium atoms are present on the growing surface in MBE InAs/GaAs(001); ii) an elastically strained InAs film on the GaAs(001) substrate should be mechanically unstable. These two well-established experimental facts may be highly relevant and should be taken into account in interpreting InAs QD formation. Finally, the authors speculate that the formation of an InAs QD is more likely to be a collective event involving a large number of both indium and arsenic atoms simultaneously or, alternatively, a morphological/structural transformation in which a single atomic InAs sheet is transformed into a three-dimensional InAs island, accompanied by the rehybridization from the sp 2-bonded to sp 3-bonded atomic configuration of both indium and arsenic elements in the heteroepitaxial growth system.

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Dynamic scaling of the island-size distribution and percolation in a model of submonolayer molecular-beam epitaxy

Cited by 331 publications

References 45 publications

High magnetic moments and anisotropies forFexCo1−xmonolayers on Pt(111)

High magnetic moments and anisotropies forFexCo1−xmonolayers on Pt(111)

Evolution of crystalline domain size and epitaxial orientation of CdTe/Si(111) quantum dots

Self-assembly of InAs quantum dots on GaAs(001) by molecular beam epitaxy

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