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Coarsening is a very common phenomenon that has a crucial impact on the average grain size and properties of materials. However, our current understanding of coarsening is mainly based on the mean-field theories or ex situ observations, and the influence of transient process-related phenomena, such as grain rotation, inverse growth, etc., on coarsening was not considered. In this work, we simulated the coarsening process of supported nanograins by a phase-field crystal (PFC) model. Our simulations show that the inverse coarsening phenomenon might occur under the influence of the substrate, where small grains grow at the expense of the large ones. We found that the substrate-induced grain rotation has a significant effect on the appearance of inverse coarsening, and the average size growth velocity of inverse coarsening is far slower than that of normal coarsening. Furthermore, the influences of initial grain size, misorientations, pinning potential strength, and the lattice mismatch on the coarsening of biocrystal systems are discussed in detail.

In metallic transition metal dichalcogenides (TMDs), which remain superconducting down to single-layer thickness, the critical temperature T c decreases for Nb-based, and increases for Ta-based materials. This contradicting trend is puzzling, impeding the development of a unified theory. Here we study the thickness-evolution of superconducting tunneling spectra in TaS 2  heterostructures. The upper critical field H c2 is strongly enhanced towards the single-layer limit - following H c 2 ∝ T c 2 . The same ratio holds for the entire family of intrinsically metallic 2H-TMDs, covering 4 orders of magnitude in H c2 . Using Gor'kov's theory, we calculate the suppression of T c by the competing charge density wave (CDW) order, which affects the quasiparticle density of states and the resulting T c and H c2 . The latter is found to be universally enhanced by two orders of magnitude. Our results substantiate CDW as the key determinant factor limiting T c across the TMD family., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Top-down fabricated nanoantenna architectures of both metallic and dielectric materials show powerful functionalities for Raman and fluorescence enhancement with relevance to single molecule sensing while inducing directionality of chromophore emission with implications for single photon sources. We synthesize the smallest bow-tie nanoantenna by selective tip-to-tip fusion of two tetrahedral colloidal quantum dots (CQDs) forming a dimer. While the tetrahedral monomers emit non-polarized light, the bow-tie architecture manifests nanoantenna functionality of enhanced emission polarization along the bow-tie axis, as predicted theoretically and revealed by single-particle spectroscopy. Theory also predicts the formation of an electric-field hotspot at the bow-tie epicenter. This is utilized for selective light-induced photocatalytic metal growth at that location, unlike growth on the free tips in dark conditions, thus demonstrating bow-tie dimer functionality as a photochemical reaction center., (© 2021 Wiley-VCH GmbH.)