Domain-walls formation in binary nanoscopic finite systems

Using a simple one-dimensional Frenkel-Kontorowa type model, we have demonstrated that finite commensurate chains may undergo the commensurate-incommensurate (C-IC) transition when the chain is contaminated by isolated impurities attached to the chain ends. Monte Carlo (MC) simulation has shown that...

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Автори: Patrykiejew, A., Sokołowski, S.
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Опубліковано: Інститут фізики конденсованих систем НАН України 2014
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Цитувати:Domain-walls formation in binary nanoscopic finite systems / A. Patrykiejew, S.Sokołowski // Condensed Matter Physics. — 2014. — Т. 17, № 2. — С. 23605:1-9 — Бібліогр.: 32 назв. — англ.

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spelling irk-123456789-1527812019-06-13T01:26:33Z Domain-walls formation in binary nanoscopic finite systems Patrykiejew, A. Sokołowski, S. Using a simple one-dimensional Frenkel-Kontorowa type model, we have demonstrated that finite commensurate chains may undergo the commensurate-incommensurate (C-IC) transition when the chain is contaminated by isolated impurities attached to the chain ends. Monte Carlo (MC) simulation has shown that the same phenomenon appears in two-dimensional systems with impurities located at the peripheries of finite commensurate clusters. 2014 Article Domain-walls formation in binary nanoscopic finite systems / A. Patrykiejew, S.Sokołowski // Condensed Matter Physics. — 2014. — Т. 17, № 2. — С. 23605:1-9 — Бібліогр.: 32 назв. — англ. 1607-324X arXiv:1407.2408 DOI:10.5488/CMP.17.23605 PACS: 64.70.Rh, 68.55.Ln, 64.60.an http://dspace.nbuv.gov.ua/handle/123456789/152781 en Condensed Matter Physics Інститут фізики конденсованих систем НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
description Using a simple one-dimensional Frenkel-Kontorowa type model, we have demonstrated that finite commensurate chains may undergo the commensurate-incommensurate (C-IC) transition when the chain is contaminated by isolated impurities attached to the chain ends. Monte Carlo (MC) simulation has shown that the same phenomenon appears in two-dimensional systems with impurities located at the peripheries of finite commensurate clusters.
format Article
author Patrykiejew, A.
Sokołowski, S.
spellingShingle Patrykiejew, A.
Sokołowski, S.
Domain-walls formation in binary nanoscopic finite systems
Condensed Matter Physics
author_facet Patrykiejew, A.
Sokołowski, S.
author_sort Patrykiejew, A.
title Domain-walls formation in binary nanoscopic finite systems
title_short Domain-walls formation in binary nanoscopic finite systems
title_full Domain-walls formation in binary nanoscopic finite systems
title_fullStr Domain-walls formation in binary nanoscopic finite systems
title_full_unstemmed Domain-walls formation in binary nanoscopic finite systems
title_sort domain-walls formation in binary nanoscopic finite systems
publisher Інститут фізики конденсованих систем НАН України
publishDate 2014
url http://dspace.nbuv.gov.ua/handle/123456789/152781
citation_txt Domain-walls formation in binary nanoscopic finite systems / A. Patrykiejew, S.Sokołowski // Condensed Matter Physics. — 2014. — Т. 17, № 2. — С. 23605:1-9 — Бібліогр.: 32 назв. — англ.
series Condensed Matter Physics
work_keys_str_mv AT patrykiejewa domainwallsformationinbinarynanoscopicfinitesystems
AT sokołowskis domainwallsformationinbinarynanoscopicfinitesystems
first_indexed 2025-07-14T04:16:36Z
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fulltext Condensed Matter Physics, 2014, Vol. 17, No 2, 23605: 1–9 DOI: 10.5488/CMP.17.23605 http://www.icmp.lviv.ua/journal Domain-walls formation in binary nanoscopic finite systems A. Patrykiejew, S. Sokołowski Department for the Modelling of Physico-Chemical Processes, Faculty of Chemistry, Maria Curie-Sklodowska University, 20031 Lublin, Poland Received February 24, 2014, in final form May 6, 2014 Using a simple one-dimensional Frenkel-Kontorowa type model, we have demonstrated that finite commensu- rate chains may undergo the commensurate-incommensurate (C-IC) transition when the chain is contaminated by isolated impurities attached to the chain ends. Monte Carlo (MC) simulation has shown that the same phe- nomenon appears in two-dimensional systems with impurities located at the peripheries of finite commensu- rate clusters. Key words: binary mixture, commensurate-incommensurate transitions, Monte Carlo simulation, finite systems, Frenkel-Kontorova model PACS: 64.70.Rh, 68.55.Ln, 64.60.an 1. Introduction In modern nanotechnologies one often deals with very small systems of countable numbers of atoms or molecules. In such cases, the finite size and boundary effects are large and bound to significantly affect the properties of the system with respect to its bulk counterpart [1]. Another important problem is the purity of small systems. While tiny amounts of impurities may be unimportant in macro-scale, the behavior of nanoscopic systems is considerably influenced even by a small number of impurity atoms [2]. Among the systems in which the presence of impurities may be of importance are those exhibiting the C-IC transition. The C-IC transitions have been experimentally observed in a variety of systems including adsorbed films, [3–6] intercalated compounds [7, 8] composite crystals [9] and magnetically ordered structures of rare-earth compounds [10]. Theoretical studies of C-IC transitions have focused on the domain wall description of incommensurate phases [11–14]. According to the domain wall formalism, the IC phase is a collection of C domains separated by domain walls. The density within the domain walls may be lower or higher than the density of commensurate domains. In the former case, the walls are light and superlight, while in the latter the walls are heavy and superheavy [13]. The simplest theoretical approach which predicts the formation of domain walls is the one-dimen- sional Frenkel-Kontorova model [15]. The original FK model assumes that an infinite chain of atoms interacting via harmonic potential at zero temperature is subjected to a periodic (sinusoidal) external field. Depending on the misfit between the equilibrium distance of the harmonic potential, the period and amplitude of the external field, the FK model is capable of describing the C-IC transition. The FK model has been extended to two-dimensional systems [16, 17] to mixtures [18], systems with disorder [19] and has also been used to study finite chains [20–22]. The NPT Monte Carlo simulation has demonstrated [23, 24] that finite one-dimensional chains, ei- ther uniform or subjected to periodic field, exhibit structures that cannot appear in infinite chains. In particular, it has been shown that the chain experiences very large density fluctuations. In the case of chains on a periodic substrate, a number of different structures (registered, free floating, domain-wall © A. Patrykiejew, S. Sokołowski, 2014 23605-1 http://dx.doi.org/10.5488/CMP.17.23605 http://www.icmp.lviv.ua/journal A. Patrykiejew, S. Sokołowski incommensurate and resulting from the chain fragmentation) have been found to appear during a single run. In one of our recent papers [25], we have shown that finite two-dimensional clusters of Kr adsorbed on graphite undergo the C-IC phase transition when contaminated by small amounts of Ar atoms. Com- puter simulation has demonstrated that the transition occurs already when the boundaries of a finite krypton island are covered with a single layer of argon atoms. In this paper we address the issue of the influence of impurities on the behavior of finite one- and two- dimensional (1D and 2D) systems. We are interested in the effects of impurities located at the peripheries of finite 1D chains and 2D clusters of atoms subjected to the periodic external field. The field is assumed to be strong enough to enforce the formation of commensurate structures in pure systems and we con- sider the possibility of the C-IC transition driven by the presence of impurities. The paper is organized as follows. In the next section we discuss the behavior of one-dimensional systems in the framework of a modified Frenkel-Kontorova model. Then, in the third section we consider two-dimensional finite systems studied by Monte Carlo simulation. In the final section we summarize our findings. 2. One-dimensional Frenkel-Kontorova model At first, we have considered a simple 1D finite chain of atoms at zero temperature and used the Frenkel-Kontorova (FK) model [15]. The energy of a finite chain consisting of N atoms subjected to a periodic external potential and containing impurities can be written as follows: E = 1 2 { N−1∑ i=1 Ki [xi+1 −xi −bi ]2 + N∑ i=1 vi [1−cos(2πxi /a)] } , (2.1) where Ki and bi are the elastic constant and the equilibrium distance for the pair (i , i +1) and vi is the amplitude of the external field for the i -th particle. Having introduced the displacements ui = xi /a −pi (i = 1,2, . . . N ) with p being a positive integer (in this work we set p = 2), the energy given by eqn.(2.1) can be rewritten in units of K0a2/2 (K0 being the elastic constant for a pure chain) as follows: E = N−1∑ i=1 K̂i [ui+1 −ui −mi ]2 + N∑ i=1 v̂i [1−cos(2πui )]. (2.2) In general, the elastic constants K̂i (the misfits mi ) can assume one of three possible values k0,0 ≡ 1, k0,im or kim,im (m0,0,m0,im ormim,im) depending on the composition of the pair (i , i+1), and the amplitude v̂i = vi /a2K0 is equal either to v0 or to vim. In order to find the equilibrium configuration of the chain, the energy should attain its minimum value, specified by the condition stating that the forces fi =−∂E/∂ui = 0 for all i . We consider the systems in which a single impurity atom is located at one end of the chain (class I) and the systems with two impurity atoms located at both ends of the chain (class II) and put k0,im = kim and m0,im = mim. The behavior of pure chains depends on m0 and v0. For the assumed value of m0 = −0.1, pure chains are commensurate when v0 exceeds the critical value v0,c ≈ 0.004950. The calculations have been done for N between 21 and 401 and v0 = 0.006. The first series of calculations have been carried out for kim = 1.0, while vim and mim have been varied. Figure 1 shows the example of the results obtained for the chains with N = 41,mim =−0.25 and different values of vim. The lower and upper panels of figure 1 show the results for the systems of class I and II, respectively. It is evident that the systems belonging to both classes exhibit a qualitatively similar behavior. Of course, the systems of the class I lack the symmetry of atomic displacements with respect to the central atom. For vim lower (higher) than vim,l (vim,u), the chain remains commensurate, while for intermediate values of vim, there appear incommensurate structures with domain walls. When vim is lower than vim,l, the energy cost to put the impurity out of registry position is low and the impurity can exhibit large displacements from the commensurate position, while the rest of the chain assumes a commensurate structure due to the domination of the surface over the elastic interaction. On the other hand, when vim > vim,u, the impurity is strongly pinned by the surface potential and the chain retains 23605-2 Domain-walls in finite systems Figure 1. (Color online) Atomic displacements vs. atomic positions for the systems of class I (part a) and II (part b) and different values of vim (given in the figure). The calculations have been done N = 41, mim = −0.25 and kim = 1.0. The insets show the changes of the average nearest-neighbor distance vs. vim The regions marked by C and ks (k = 1,2,3,4) correspond to the commensurate structure to the incommensurate structures with k domain walls, respectively. the commensurate structure. Figure 1 shows that when vim > vim,u, the displacements of impurities are considerably lower than when vim < vim,l. For intermediate values of vim, the gain in elastic energy due to transition into the incommensurate structure is larger than the loss of surface energy. The insets to figure 1 show the changes of the average nearest-neighbor distance with vim. In both classes of systems, we have found a series of transitions characterized by a different number of domain walls. The calculations for chains with N up to 401 have shown that in longer chains a larger number of structures appear, and it seems that in the limit of N →∞ the transitions form a harmless staircase [11]. The values of vim,l and vim,u change with mim and there is a critical value of mim,c for which the difference ∆vim = vim,u−vim,l goes to zero (figure 2). In the particular examples considered here (N = 41 and kim = 1.0), mim,c ≈ −0.1856 for the systems of class I and II. The inset to figure 2 shows that ∆vim scales withmim,c−mim as follows: ∆vim∝ (mim,c−mim)1/2, k = 1,2. (2.3) The same scaling appears for the transitions between different incommensurate structures, but the value ofmim,c for each transition is different (figure 2). We have then investigated the effects due to changes in the magnitude of kim. Figure 3 gives the example of results for the systems of class I. We see that the values of vim at the transitionsC −1s, 1s−2s and 2s −3s are nearly independent of kim, while those corresponding to transitions 3s −2s, 2s −1s and 1s −C (leading to the recovery of commensurability), exhibit a logarithmic dependence on kim. The logarithmic dependence of vim on kim at transitions 3s−2s, 2s−1s and 1s−C has the same origin as the C-IC transition in a pure FK model [11]. On the other hand, the mechanism of transitions leading to commensurability when vim becomes very low is different. For sufficiently low vim, the energy cost to put 23605-3 A. Patrykiejew, S. Sokołowski Figure 2. The phase diagrams showing the dependence of the difference between the upper and lower values of vim at the transition points (∆vim(α,β)) between different structures (α,β) and the impurity misfit mim(α,β). The calculations have been done for N = 41 and kim = 1.0 and for the classes I and II. The inset shows the scaling plot for the C-IC transition. the impurity out of registry position and to restore the commensurate positions in the rest of the chain is low. Consequently, the impurity can exhibit a large displacement from the commensurate position, while the rest of the chain assumes a commensurate structure due to the domination of surface energy over the elastic energy. This is illustrated in the inset to figure 3, which shows atomic displacements for the Figure 3. (Color online) The phase diagrams showing the dependence of vim on kim at the transition points between different structures. The calculations have been done for N = 41 and mim = −0.24. The inset shows the atomic displacements versus actual atomic positions in the commensurate phase for vim = 0.003 and vim = 0.017 when kim = 1.0. Filled symbols mark the impurity atom. 23605-4 Domain-walls in finite systems systems with kim = 1.0 and vim = 0.003 and vim = 0.017, while the rest of the parameters have been kept the same as in the main figure. Of course, there is an asymmetry of displacements in the chain but it is very small. In the commensurate phase at high values of vim = 0.017, the displacements at both ends are nearly the same. Another question is whether a single impurity can drive the incommensurate system into commen- surability? The answer is no. On the other hand, two impurities located at both ends of the chains do lead to the recovery of commensurability when vim is sufficiently high. This is just the same as with the rope pinned either to one or two walls. In the first case, the rope hangs down freely. In the latter, the rope pinned to the opposite walls can be expanded to some extent. In the harmonic approximation, the chain always retains integrity, although when the interaction potential allows for dissociation, the chain may rupture [23, 24, 26] rather than restore the C structure. 3. Two-dimensional finite clusters The phenomenon of reentrant commensurability is not restricted to the above discussed simple 1D model. It also appears in more realistic 2D systems in the ground state and at finite temperatures. To demonstrate this, we have performed MC simulation in the canonical ensemble for finite clusters dec- orated with impurities at the boundaries. The particles of A and B (impurity) have been placed in the substrate field vi (x, y) =−Vi {cos(q1r)+cos(q2r)+cos[(q1 −q2)r]} (3.1) corresponding to the graphite basal plane, where Vi is the amplitude of the potential for the i th compo- nent and q1 and q2 are the reciprocal lattice vectors of the graphite basal plane. The initial configurations have been a hexagon of a perfectly ordered ( p 3×p 3)R30◦ structure consisting of NA z atoms of A and NB atoms of B placed along the one edge (case I), the adjacent three edges (case II) or along all six edges (case III) of the cluster. The interaction between the particles has been represented by the LJ(12,6) poten- tial with the fixed σA A = 1.46a (a = 2.46 Å is the graphite lattice constant taken as the unit of length) and εA A/kB = 170 K (assumed to be a unit of energy) andV ∗ A =VA/εA A = 0.12. In order to reduce the tendency of B atoms towards aggregation, we have put εBB = 0.5εA A , while εAB has been assumed to be equal to εA A . The parameters σBB =σAB and VB have been varied. The simulations have been carried out for the systems with NA = 271 and NB = 11 (case I), NB = 33 (case II) and NB = 66 (case III). Besides, we have also performed some runs for a larger system corre- sponding to case III, with NA = 811 and NB = 114 as well as with NA = 1189 and NB = 138. The simula- tion has been performed at reduced temperatures T ∗ = kBT /εA A between 0.005 and 0.3. The formation of domain walls in the system has been monitored using the order parameter [25, 27] φ(r) = cos(q1r)+cos(q2r)+cos[(q1 −q2)r], (3.2) and assuming that the atom is commensurate (incommensurate) when φ > 0 (φ É 0). We have calcu- lated the average numbers of incommensurate atoms A and B neglecting the atoms located at the patch boundaries, i.e., those with less than 5 nearest neighbors. It has been found that for any value of σ∗ BB = σBB /a between 1.34 and 1.37 and for sufficiently low and sufficiently high values of V ∗ B , the systems remain commensurate, while for the intermediate values of V ∗ B , there appear networks of heavy walls separating commensurate domains. In general, the results at low temperatures are qualitatively very similar to those obtained for 1D FK model. In particular, we have observed the formation of IC structures in the cases I, II and III, though the structure of the domain-wall networks is different in all cases. In general, the walls tend to assume the orientations perpendicular to the edges decorated with the impurity atoms. Therefore, in case III, we have found regular networks like that given in the leftmost part offigure 4. On the other hand, the systems with only one or three adjacent edges decorated by impurities form irregular networks of domain walls (see the middle and rightmost panels to figure 4). The region of V ∗ B over which the IC phase is stable at low temperatures gradually decreases when the size of impurity atoms increases, so that for sufficiently large impurity atoms, only the C phase occurs independently of the magnitude ofV ∗ B (see figure 5). The calculations for the larger systemwith NA = 811 23605-5 A. Patrykiejew, S. Sokołowski Figure 4. (Color online) The examples of snapshots for the system with σ∗ BB = 1.36 and V ∗ B = 0.12 at T∗ = 0.02 corresponding to the three cases considered. Shaded circles represent B atoms. Open (filled) circles correspond to the commensurate (incommensurate) A atoms. and NB = 114 (case III) have shown that maximum value of σ∗ AB above which the C-IC transition does not appear slightly increases with the system size. Moreover, the simulations performed for larger systems have also demonstrated that at low temperatures the size of C domains does not change and only their number increases. This result is quite similar to that obtained for 1D FK model for the chains of different length. This is demonstrated by the snapshots given in the leftmost part of figure 4 and in figure 6. The impurity induced changes of the surface stress are responsible for the C-IC transition, which leads to the compression of the finite island. When the amplitude of the impurity surface potential, V ∗ B , is very low, the presence of impurities at the cluster boundaries does not appreciably affect the strain of the atoms in the cluster. Therefore, the surface stress of the impurity decorated island does not match differently from that of the pure system. For sufficiently large values of V ∗ B , the impurities are strongly pinned over the surface potential minima as well as do not enlarge the strain in the island. Therefore, for sufficiently low and high V ∗ B , the system retains the C structure. For intermediate values of V ∗ B , the competing atom-atom and atom-external field interactions lead to a sufficiently large increase of a surface stress in order to trigger the C-IC transition. One should note a similarity of the herein reported impurity driven C-IC transition to the behavior of metal nanowires [28] and to the formation of IC phases in the subjected to uniaxial compression self-assembledmonolayer gold nanoparticles supported on a fluid [29]. The results presented here describe only the low temperature behavior of the systems. The simulation has demonstrated that upon an increase of temperature, the IC structure gradually changes and the C structure is restored at temperatures still below the melting point of the cluster. The effects of thermal excitations on the domain-wall networks will be discussed elsewhere. Figure 5. (Color online) The phase diagram showing the locations (V ∗ B versus σ ∗ AB ) of C-IC transition in the limit of T∗ → 0 in the systems with NA = 271 and different concentration of impurity atoms. 23605-6 Domain-walls in finite systems Figure 6. (Color online) The example of snapshot for the system with NA = 1189 and NB = 138, σAB = 1.365 and V ∗ B = 0.08 recorded at T∗ = 0.01 K. Shaded circles represent B atoms. Open and filled circles correspond to the commensurate and incommensurate A atoms. 4. Summary In this work we have studied the impurity driven commensurate-incommensurate transitions in one- and two-dimensional finite systems at zero temperature. In the case of one-dimensional finite chains, we have considered the situations in which the impurity is located at one and two ends of the chain. It has been shown that in both situations, the C-IC transition occurs when the amplitude of the external field experienced by the impurity atoms falls into the region between the lower and upper threshold values. These limiting values of vim depend upon the parameters characterizing the interaction between the atoms in the main chain, the amplitude of external field acting on the main chain atoms and the interaction between the main chain and the impurities. The number of solitons (domain walls) in the IC structure is different for the chains with one and two ends decorated with the impurity atoms and also depends upon the vim. This behavior is a consequence of different symmetry properties of the system. In the case of two-dimensional finite clusters, a very similar C-IC transition has been found. In par- ticular, we have observed that the transition occurs when only a part of the cluster boundary is covered with a single row of impurity atoms. Also, by analogy to the results of one-dimensional FK model, the transition occurs only between the lower and upper threshold values of vim. It should be noted that the C-IC transition observed in two-dimensional systems occurs only when the parameters entering the potential describing the interactions between A A, AB , and BB atoms are suit- ably chosen. First of all, the components A and B should not exhibit the tendency towards mixing. Oth- erwise, the impurity atoms B are likely to penetrate the patch and different scenarios are possible. One, is the formation of a mixed commensurate phase. This has been found in the case of Ar-Kr finite patches at sufficiently high temperatures [25], when the AB interaction potential parameters were obtained us- ing the standard Lorentz-Berthelot mixing rules. The same mixture exhibits a different behavior at low temperatures, and does undergo the C-IC transition, although with the domain walls preferentially made of Ar atoms. Another requirement is that atoms A should tend to order into the C phase, while atoms B should order into the IC phase. This imposes certain restrictions on the choice of σ∗ A A , σBB and the values of V ∗ A and V ∗ B . In particular, σ ∗ A A and V ∗ A should assume the values ensuring that a pure A patch is commensurate, but are likely to undergo the C-IC transition when the density exceeds the monolayer capacity or when subjected to an external force due to the presence of impurity atoms along the patch boundaries. Thus, V ∗ A cannot be too low or to high and the misfit between the sizes of surface lattice and adsorbate atoms is rather small. A good example of such a system is krypton adsorbed on graphite [5]. In fact, the parameters σ∗ A A and V ∗ A used here are rather close to those describing the krypton adsorbed on the graphite basal plane [25]. On the other hand, the values of σBB and V ∗ B should favor the formation of IC phase by pure component B . Thus, the misfit between the size of B atoms and the surface lattice 23605-7 A. Patrykiejew, S. Sokołowski should be sufficiently large (it can be positive as well as negative) and V ∗ B should be sufficiently small. However, there is still another requirement for the appearance of C-IC transition in finite patches. The AB interaction should be sufficiently strong so that the layer of B atoms along the patch boundary is stable. Otherwise, the atoms B would prefer to form clusters rather than stay at the patch boundary. Besides, this condition is also necessary to exert a sufficiently large force upon the atoms A inside the finite patch to trigger the C-IC transition. Usually, the C-IC transition occurs only when the film density exceeds the density of a fully filled commensurate phase. For the C-IC transition to occur in finite patches, the stability of the C phase should be low enough so that a rather small force exerted by a thin layer of impurity atoms along the patch boundary is able to drive the C-IC transition. From our earlier studies of adsorption of Ar-Kr, Ar-Xe and Kr-Xe mixtures [25, 30–32] on graphite it follows that only in the case of Ar-Kr mixture the C-IC transition occurs at submonolayer densities in finite patches of adsorbed phase. One expects that at higher temperatures, thermal excitations may considerably influence the effects observed. This problem is currently under study and the results will be published elsewhere. Acknowledgements This work was supported by ERA under the Grant PIRSES 268498. References 1. Esfarjani K., Mansoori G.A., In: Handbook of Theoretical and Computational Nanotechnology, Vol. 10, Rieth M., Schommers W. (Eds.), American Scientific Publishers, Los Angeles, 2005, 1–45. 2. Hwang I.-S., Fang C.-K., Chang S.-H., Phys. Rev. B, 2011, 83, 134119. doi:10.1103/PhysRevB.83.134119. 3. Jaubert M., Glachant A., Bienfait M., Boato G., Phys. Rev. Lett., 1981, 46, 1679; doi:10.1103/PhysRevLett.46.1679. 4. Krim J., Suzanne J., Shechter H., Wang R., Taub H., Surface Sci., 1985, 162, 446; doi:10.1016/0039-6028(85)90933-1. 5. Stephens P.W., Heiney P.A., Birgeneau R.J., Horn P.M., Moncton D.E., Brown G.S., Phys. Rev. B, 1984, 29, 3512; doi:10.1103/PhysRevB.29.3512. 6. Usachov D., Dobrotvorskii A.M., Varykhalov A., Rader O., Phys. Rev. B, 2008, 78, 085403; doi:10.1103/PhysRevB.78.085403. 7. Clarke R., In: Ordering in Two Dimensions, Sinha S.K. (Ed.), North-Holland, Amsterdam, 1980, p. 53–58. 8. Li L.J., Lu W.J., Zhu X.D., Ling L.S., Qu Z., Sun Y.P., Europhys. Lett., 2012, 97, 67005; doi:10.1209/0295-5075/97/67005. 9. Nuss J., Pfeiffer S., van Smallen S., Jansen M., Acta Crystalogr. B, 2010, 66, 27; doi:10.1107/S0108768109053312. 10. Vokhmyanin A.P., Lee S., Jang K.-H., Podlesnyak A.A., Keller L., Prokeš K., Sikolenko V.V., Park J.-G., Skryabin Yu.N., Pirogov A.N., J. Magn. Magn. Mater., 2006, 300, e411; doi:10.1016/j.jmmm.2005.10.179. 11. Bak P., Rep. Prog. Phys., 1982, 45, 587; doi:10.1088/0034-4885/45/6/001. 12. Huse D.A., Fisher M., Phys. Rev. B, 1984, 29, 239; doi:10.1103/PhysRevB.29.239. 13. Den Nijs M., In: Phase Transitions and Critical Phenomena, Vol. 12, Domb C., Lebowitz J.L. (Eds.), Acedemic Press, London, 1988, p. 219–333. 14. Patrykiejew A., Sokołowski S., Binder K., Surface Sci., 2002, 512, 1; doi:10.1016/S0039-6028(02)01702-8. 15. Frenkel Y.I., Kontorova T., Zh. Eksp. Theor. Fiz., 1938, 8, 1340 (in Russian). 16. Lomdahl P.S., Srolovitz D.J., Phys. Rev. Lett., 1986, 57, 2702; doi:10.1103/PhysRevLett.57.2702. 17. Hamilton J.C., Phys. Rev. Lett., 2002, 88, 126101; doi:10.1103/PhysRevLett.88.126101. 18. Daruka I., Hamilton J.C., J. Phys.: Condens. Matter, 2003, 15, 1827; doi:10.1088/0953-8984/15/12/302. 19. Braun O.M., Kivshar J.S., Phys. Rep., 1998, 306, 1; doi:10.1016/S0370-1573(98)00029-5. 20. Braiman Y., Baumgarten J., Jortner J., Klafter J., Phys. Rev. Lett., 1990, 65, 2398; doi:10.1103/PhysRevLett.65.2398. 21. Braiman Y., Baumgarten J. Klafter J., Phys. Rev. B, 1993, 47, 11159; doi:10.1103/PhysRevB.47.11159. 22. Vanossi A., Franchini A., Bortolani V., Surface Sci., 2002, 502-503, 437; doi:10.1016/S0039-6028(01)01990-2. 23. Phillips J.M., Dash J.G., J. Stat. Phys., 2005, 120, 721; doi:10.1007/s10955-005-5252-x. 24. Hartnett A.S., Phillips J.M., Phys. Rev. B, 2008, 77, 035408; doi:10.1103/PhysRevB.77.035408. 25. Patrykiejew A., Rżysko W., Sokołowski S., J. Phys. Chem. C, 2011, 116, 753; doi:10.1021/jp208323b. 26. Markov I., Trayanov A., J. Phys.: Condens. Matter, 1990, 2, 6965; doi:10.1088/0953-8984/2/33/009. 27. Houlrik J. M., Landau D.P., Phys. Rev. B, 1991, 44, 8962; doi:10.1103/PhysRevB.44.8962. 28. Diao J., Gall K., Dunn M.L., Nat. Mater., 2003, 2, 656; doi:10.1038/nmat977. 23605-8 http://dx.doi.org/10.1103/PhysRevB.83.134119 http://dx.doi.org/10.1103/PhysRevLett.46.1679 http://dx.doi.org/10.1016/0039-6028(85)90933-1 http://dx.doi.org/10.1103/PhysRevB.29.3512 http://dx.doi.org/10.1103/PhysRevB.78.085403 http://dx.doi.org/10.1209/0295-5075/97/67005 http://dx.doi.org/10.1107/S0108768109053312 http://dx.doi.org/10.1016/j.jmmm.2005.10.179 http://dx.doi.org/10.1088/0034-4885/45/6/001 http://dx.doi.org/10.1103/PhysRevB.29.239 http://dx.doi.org/10.1016/S0039-6028(02)01702-8 http://dx.doi.org/10.1103/PhysRevLett.57.2702 http://dx.doi.org/10.1103/PhysRevLett.88.126101 http://dx.doi.org/10.1088/0953-8984/15/12/302 http://dx.doi.org/10.1016/S0370-1573(98)00029-5 http://dx.doi.org/10.1103/PhysRevLett.65.2398 http://dx.doi.org/10.1103/PhysRevB.47.11159 http://dx.doi.org/10.1016/S0039-6028(01)01990-2 http://dx.doi.org/10.1007/s10955-005-5252-x http://dx.doi.org/10.1103/PhysRevB.77.035408 http://dx.doi.org/10.1021/jp208323b http://dx.doi.org/10.1088/0953-8984/2/33/009 http://dx.doi.org/10.1103/PhysRevB.44.8962 http://dx.doi.org/10.1038/nmat977 Domain-walls in finite systems 29. Chua Y., Leahy B., Zhang M., You S., Lee K.Y.C., Coppersmith S.N., Lin B., PNAS, 2013, 110, 824; doi:10.1073/pnas.1101630108. 30. Patrykiejew A., Condens. Matter Phys., 2012, 15, 23601. doi:10.5488/CMP.15.23601. 31. Patrykiejew A., Sokołowski S., J. Chem. Phys., 2012, 136, 144702; doi:10.1063/1.3699330. 32. Patrykiejew A., J. Phys.: Condens. Matter, 2013, 25, 015001; doi:10.1088/0953-8984/25/1/015001. Формування домен-стiнки в бiнарних наноскопiчних скiнченних системах А. Патрикєєв, С. Соколовскi Вiддiл моделювання фiзико-хiмiчних процесiв, Унiверситет Марiї Кюрi-Склодовської, Люблiн, Польща Використовуючи просту одновимiрну типову модель Френкеля-Конторової, ми показали, що скiнченнi спiввимiрнi ланцюжки можуть зазнавати спiввимiрний-неспiввимiрний (C-IC) перехiд, якщо ланцюжок забруднений iзольованими домiшками, дочепленими до кiнцiв ланцюжка. За допомогою методу Монте Карло (MC) показано, що таке ж явище виникає в двовомiрних системах з домiшками, розмiщеними на периферiї скiнчених спiввимiрних кластерiв. Ключовi слова: бiнарна сумiш, спiввимiрнi-неспiввимiрнi переходи, симуляцiї Монте Карло, скiнченнi системи, модель Френкеля-Конторової 23605-9 http://dx.doi.org/10.1073/pnas.1101630108 http://dx.doi.org/10.5488/CMP.15.23601 http://dx.doi.org/10.1063/1.3699330 http://dx.doi.org/10.1088/0953-8984/25/1/015001 Introduction One-dimensional Frenkel-Kontorova model Two-dimensional finite clusters Summary