Vacancies in Self‐Assembled Crystals: An Archetype for Clusters Statistics at the Nanoscale

Pariente, Jose Ángel; Caselli, Niccolò; Pecharromán, Carlos; Blanco, Alberto; López, Cefe

doi:10.1002/smll.202002735

Cited by 3 publications

(3 citation statements)

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“…However, most experiments on colloid clusters report mass transport dominated by attachment-detachment at the edges [56]. Our analysis can be adapted to vacancy clusters [5,57,58] with volume-preserving detachmentdiffusion-reattachment events. Moreover, other two or three-dimensional lattices also could be analyzed.…”

mentioning

confidence: 99%

Controlling the shape of small clusters with and without macroscopic fields

Boccardo,

Pierre-Louis

2022

Preprint

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Despite major advances in the understanding of the formation and dynamics of nano-clusters in the past decades, theoretical bases for the control of their shape are still lacking. We investigate strategies for driving fluctuating few-particle clusters to an arbitrary target shape in minimum time with or without an external field. This question is recast into a first passage problem, solved numerically, and discussed within a high temperature expansion. Without field, large-enough low-energy target shapes exhibit an optimal temperature at which they are reached in minimum time. We then compute the optimal way to set an external field to minimize the time to reach the target, leading to a gain of time that grows when increasing cluster size or decreasing temperature. This gain can shift the optimal temperature or even create one. Our results could apply to clusters of atoms at equilibrium, and colloidal or nanoparticle clusters under thermo-or electrophoresis.

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mentioning

confidence: 99%

Controlling the shape of small clusters with and without macroscopic fields

Boccardo,

Pierre-Louis

2022

Preprint

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“…Let's not forget that γ depends on the number of vacancies in the defect, their shape, the average dielectric function of their environment and their relative abundance. Regarding the latter, size, shape, and amount greatly increase for large vacancies concentration, [ 29 ] rendering its contribution highly non‐trivial and difficult to grasp with our simple model. This fact is probably the main reason behind poorer fitting for higher ρ .…”

Section: Field Enhancementmentioning

confidence: 99%

“…These structures have been proved to be excellent archetypes for controlled insertion of random vacancies. [ 29 ] The asymmetric peaks obtained in reflectance spectra can be described as Fano resonances brought about by the interference between the photonic band gap reflection and the emerging background diffusion caused by vacancies and relying on the field enhancement at such defects. At a singular composition, signaled by the change of sign of the q parameter, a structure emerges where Bragg reflectance not just decreases but completely vanishes.…”

Section: Introductionmentioning

confidence: 99%

Fano‐Like Resonance from Disorder Correlation in Vacancy‐Doped Photonic Crystals

Pariente

Bayat

Blanco

et al. 2023

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By preparing colloidal crystals with random missing scatterers, crystals are created where disorder is embodied as vacancies in an otherwise perfect lattice. In this special system, there is a critical defect concentration where light propagation undergoes a transition from an all but perfect reflector (for the spectral range defined by the Bragg condition), to a metamaterial exhibiting an enhanced transmission phenomenon. It is shown that this behavior can be phenomenologically described in terms of Fano‐like resonances. The results show that the Fano's parameter q experiences a sign change signaling the transition from a perfect crystal exhibiting a reflectance Bragg peak, through a state where background scattering is maximum and Bragg reflectance reaches a minimum to a point where the system reenters a low scattering state recovering ordinary Bragg diffraction. A simple dipolar model considering the correlation between scatterers and vacancies is proposed and the reported evolution of the Fano‐like scattering is explained in terms of the emerging covariance between the optical paths and polarizabilities and the effect of field enhancement in photonic crystal (PhC) defects.

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