Self-ordered magnetic <i>α</i>-FeSi2 nano-stripes on Si(111)

Tripathi, J.; Markovich, Gil; Goldfarb, I.

doi:10.1063/1.4812239

Cited by 37 publications

(26 citation statements)

References 52 publications

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“…Indeed, there is a set of reports on the growth of such interfaces on Si(001) substrate by molecular beam exitaxy methods (Tarasov et al, 2016;Pushkarev et al, 2018). At the same time, numerous experimental works show this compound tends more to form free-standing nanocrystals partially embedded into silicon matrix (Tripathi et al, 2013;Tarasov et al, 2016;Chen et al, 2006;Tarasov et al, 2017;Pushkarev et al, 2018), often with endotaxial (112)||Si(111) interface formation, in compliance with the relative favourability order of the habit planes found herein. The presence of several high-index silicon planes among the topmost ORs (||Si i.2, ||Si i.3, ||Si i.14, ||Si i.20) also suggests endotaxial growth of -FeSi 2 crystallites on Si(001).…”

Section: Atomic Configurationsupporting

confidence: 77%

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Visotin

Тарасов

Федоров

et al. 2020

Acta Crystallogr Sect B

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A pure crystallogeometrical approach is proposed for predicting orientation relationships, habit planes and atomic structures of the interfaces between phases, which is applicable to systems of low-symmetry phases and epitaxial thin film growth. The suggested models are verified with the example of epitaxial growth of -,and -FeSi 2 silicide thin films on silicon substrates. The density of near-coincidence sites is shown to have a decisive role in the determination of epitaxial thin film orientation and explains the superior quality of -FeSi 2 thin grown on Si(111) over Si(001) substrates despite larger lattice misfits. Ideal conjunctions for interfaces between the silicide phases are predicted and this allows for utilization of a thin buffer -FeSi 2 layer for oriented growth of -FeSi 2 nanostructures on Si(001). The thermal expansion coefficients are obtained within quasi-harmonic approximation from the DFT calculations to study the influence of temperature on the lattice strains in the derived interfaces. Faster decrease of misfits at the -FeSi 2 (001)||Si(001) interface compared to -FeSi 2 (001)||Si(001) elucidates the origins of temperature-driven change of the phase growing on silicon substrates. The proposed approach guides from bulk phase unit cells to the construction of the interface atomic structures and appears to be a powerful tool for the prediction of interfaces between arbitrary phases for subsequent theoretical investigation and epitaxial film synthesis. M. A. Visotin et al. -, -, -FeSi 2 and Si phases 471 research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 473 research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 479 Figure 6Temperature dependence of interface strain" " for different silicon||silicide and silicide||silicide ORs from Table 1. research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 481

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Section: Atomic Configurationsupporting

confidence: 77%

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Visotin

Тарасов

Федоров

et al. 2020

Acta Crystallogr Sect B

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“…As was pointed out in Ref. [20], the best orientation relationships, that stabilize the epitaxial α − F eSi 2 are α − F eSi 2 (201)||Si(110), α − F eSi 2 (110)||Si(110) or α − F eSi 2 (111)||Si(001). Such planes contain additional Si atoms in Si-rich alloys from Fig.…”

Section: Discussionmentioning

confidence: 93%

“…However, as was mentioned in Introduction, several recent studies [13,19,20] discovered that a ferromagnetic state arises in the films of α − F eSi 2 . The explanation of the emergence of the magnetic structure, suggested in these works, is within the commonly accepted opinion, that the magnetism arises due to an increase of Fe concentration in the material.…”

Section: A Ab Initio Calculationsmentioning

confidence: 99%

“…The used theoretical approaches, CPA in the Ref. [19] and phenomenological local environment models in Refs [13,20], take into account, however, only a part of the local environment effects because full account of them is beyond the reach of the standard CPA methods by construction, whereas the local environment models [21,22] take into account the nearest enviroment only. In Ref.…”

Section: A Ab Initio Calculationsmentioning

confidence: 99%

“…The authors of Refs. [13], [20] reported that the magnetic moments on Fe atoms µ = 1.8µ B [13] and µ = 3.3µ B [20] in α − F eSi 2 nanoislands and nano-stripes on Si (111) substrate arise. These experimental achievements have good perspective for the integration of the F eSi -based magnetic devices into silicon technology, and, therefore, demands for the detailed understanding of the physics of the magnetic moment formation in these compounds.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Self-consistent mapping: Effect of local environment on formation of magnetic moment in α−FeSi2

et al. 2017

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The Hohenberg-Kohn theorem establishes a basis for mapping of the exact energy functional to a model one provided that their charge densities coincide. We suggest here to use a mapping in a similar spirit: the parameters of the formulated multiorbital model should be determined from the requirement that the self-consistent charge and spin densities found from the ab initio and model calculations have to be as close to each other as possible. The analysis of the model allows for detailed understanding of the role played by different parameters of the model in the physics of interest. After finding the areas of interest in the phase diagram of the model we return to the ab initio calculations and check if the effects discovered are confirmed or not. Because of the last controlling step we call this approach as hybrid self-consistent mapping approach (HSCMA). As an example of the approach we present the study of the effect of silicon atoms substitution by the iron atoms and vice versa on the magnetic properties in the iron silicide α − F eSi2. The DFT+GGA calculations are mapped to the model with intraatomic Coulomb and exchange interactions, hoppings to nearest and next nearest atoms and exchange of the delocalized electrons between iron atoms; the magnetic moments on atoms and charge densities of the material are found self-consistently within the Hartree-Fock approximation.We find that while the stoichiometric α − F eSi2 is nonmagnetic, the substitutions generate different magnetic structures. For example, the substitution of three Si atoms by the F e atoms results in the ferrimagnetic structure whereas the substitution of four Si atoms by F e atoms gives rise to either the nonmagnetic or the ferromagnetic state depending on the type of local enviroment of the substitutional F e atoms. Besides, contrary to the commonly accepted statement that the destruction of the magnetic moment is controlled only by the number of F e − Si nearest neighbors, we find that actually it is controlled by the F e − F e next-nearest-neighbors' hopping parameter. This finding led us to the counterintuitive conclusion: an increase of Si concentration in F e1−xSi2+x ordered alloys may lead to a ferromagnetism. This conclusion is confirmed by the calculation within GGA-to-DFT.

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Magnetic Binary Silicide Nanostructures

2018

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In spite of numerous advantageous properties of silicides, magnetic properties are not among them. Here, the magnetic properties of epitaxial binary silicide nanostructures are discussed. The vast majority of binary transition-metal silicides lack ferromagnetic order in their bulk-size crystals. Silicides based on rare-earth metals are usually weak ferromagnets or antiferromagnets, yet both groups tend to exhibit increased magnetic ordering in low-dimensional nanostructures, in particular at low temperatures. The origin of this surprising phenomenon lies in undercoordinated atoms at the nanostructure extremities, such as 2D (surfaces/interfaces), 1D (edges), and 0D (corners) boundaries. Uncompensated superspins of edge atoms increase the nanostructure magnetic shape anisotropy to the extent where it prevails over its magnetocrystalline counterpart, thus providing a plausible route toward the design of a magnetic response from nanostructure arrays in Si-based devices, such as bit-patterned magnetic recording media and spin injectors.

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Self-ordered magnetic α-FeSi2 nano-stripes on Si(111)

Abstract: Influence of excess Fe accumulation over the surface of FePt nanoparticles: Structural and magnetic properties

Cited by 37 publications

References 52 publications

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Self-consistent mapping: Effect of local environment on formation of magnetic moment in α−FeSi2

Magnetic Binary Silicide Nanostructures

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Self-ordered magnetic α-FeSi2 nano-stripes on Si(111)

Abstract: Influence of excess Fe accumulation over the surface of FePt nanoparticles: Structural and magnetic properties

Cited by 37 publications

References 52 publications

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi2 and Si phases

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi2 and Si phases

Self-consistent mapping: Effect of local environment on formation of magnetic moment in α−FeSi2

Magnetic Binary Silicide Nanostructures

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Product

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Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases