| 研究実績の概要 |
We investigate the formation and fluctuation of a two-dimensional dodecagonal quasicrystal (DDQC) by patchy particles.
The self-assembly of two-dimensional dodecagonal quasicrystals (DDQCs) from patchy particles is investigated by Brownian dynamics simulations. The patchy particle has a five-fold rotational symmetry pattern described by the spherical harmonics Y55. From the formation of the DDQC obtained by an annealing process, we find the following mechanism. The early stage of the dynamics is dominated by hexagonal structures. Then, nucleation of dodecagonal motifs appears by particle rearrangement, and finally the motifs span the whole system. The transition from the hexagonal structure into the dodecagonal motif is coincident with the collective motion of the particles. The DDQC consists of clusters of dodecagonal motifs, which can be classified into several packing structures. By the analyses of the DDQC under fixed temperature, we find that the fluctuations are characterised by changes in the network of the dodecagonal motifs. Finally we compare the DDQCs assembled from the patchy particle system and isotropic particle system. The two systems share a similar mechanism of the formation and fluctuation of DDQCs.
By this result, we have better understanding on the mechanism, the growth of quasicrystal.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Due to COVID-19, in-person workshop and conferences were not possible, and it was hard to discuss with researchers. The procedures for submitting paper to journal were also slow. Despite the difficulties, we published one paper, joined virtual conferences and presented our work.
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| 今後の研究の推進方策 |
Patchy particles are the particles with anisotropic surface patterns or patches on specific positions on the surface. The interaction of such particles is not only dependent on the distance, but also on their mutual orientations. Therefore, the patchy particles are capable of organizing themselves into complex structures, which are important for the generation of novel materials.
One of the complex structures is quasicrystal. Quasicrystal are ordered structures lacking periodic translational symmetry. Quasicrystals may
have 5-, 10-, 12-fold rotational symmetry while crystals possess 2-, 3-, 4-, and 6-fold rotational symmetry. The quasicrystal is interesting in both theoretical and application aspects. The quasicrystal can be applied in various application such as advanced coatings, reinforced composites, magnetism. We assemble a two-dimensional dodecagonal quasicrystal from the patchy particle of fivefold symmetry by Brownian dynamics simulation. However, it is still difficult to identify the best parameters for assembling the quasicrystal structure. This kind of problem also occurs for other assembled structure.
We will apply inverse design and reinforcement learning to search for the best parameters under which a specific structure can be created. We also expect that be controlling the external driving force, the functions or properties can be control as well.
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