Entropy versus energy: The phase behavior of a hard-disk mixture in a periodic external potential

Franzrahe, Kerstin; Nielaba, Peter

doi:10.1103/physreve.76.061503

Cited by 18 publications

(26 citation statements)

References 28 publications

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“…More complex potential-induced disorder-order and disorder-disorder transitions have been theoretically investigated in mixtures, namely colloid-polymer mixtures and binary hard discs [118][119][120]. The dynamics of binary colloidal mixtures with large size disparity have been investigated without the presence of an external potential [121,122].…”

Section: Potentialsmentioning

confidence: 99%

Colloids in light fields: Particle dynamics in random and periodic energy landscapes

Evers

Hanes

Zunke

et al. 2013

Eur. Phys. J. Spec. Top.

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The dynamics of colloidal particles in potential energy landscapes have mainly been investigated theoretically. In contrast, here we discuss the experimental realization of potential energy landscapes with the help of light fields and the observation of the particle dynamics by video microscopy.The experimentally observed dynamics in periodic and random potentials are compared to simulation and theoretical results in terms of, e.g. the mean-squared displacement, the time-dependent diffusion coefficient or the non-Gaussian parameter. The dynamics are initially diffusive followed by intermediate subdiffusive behaviour which again becomes diffusive at long times. How pronounced and extended the different regimes are, depends on the specific conditions, in particular the shape of the potential as well as its roughness or amplitude but also the particle concentration. Here we focus on dilute systems, but the dynamics of interacting systems in external potentials, and thus the interplay between particle-particle and particle-potential interactions, is also mentioned briefly. Furthermore, the observed dynamics of dilute systems resemble the dynamics of concentrated systems close to their glass transition, with which it is compared. The effect of certain potential energy landscapes on the dynamics of individual particles appears similar to the effect of interparticle interactions in the absence of an external potential.

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Section: Potentialsmentioning

confidence: 99%

Colloids in light fields: Particle dynamics in random and periodic energy landscapes

Evers

Hanes

Zunke

et al. 2013

Eur. Phys. J. Spec. Top.

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show abstract

“…Recently, a binary hard-disc system with size ratio α = 0.414 has been studied by MC simulations with an external field of spatially periodic attractive lines [194,187]. For a weak external potential, de-mixing of large and small particles in the binary suspension is observed, which leads to the coexistence of ordered structures of large particles and a fluid of small ones.…”

Section: External Fieldsmentioning

confidence: 99%

Crystallization in three- and two-dimensional colloidal suspensions

Gasser

2009

J. Phys.: Condens. Matter

234

242

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Despite progress in the understanding of crystal nucleation and crystal growth since the first theories for nucleation were developed, an exact quantitative prediction of the nucleation rates in most systems has remained an unsolved problem. Colloidal suspensions show a phase behavior that is analogous to atomic or molecular systems and serve accordingly as ideal model systems for studying crystal nucleation with an accuracy and depth on a microscopic scale that is hard to reach for atomic or molecular systems. Due to the mesoscopic size of colloidal particles they can be studied in detail on the single-particle level and their dynamics is strongly slowed down in comparison with atomic or molecular systems, such that the formation of a crystal nucleus can be followed in detail. In this review, recent progress in the study of homogeneous and heterogeneous crystal nucleation in colloids and the controlled growth of crystalline colloidal structures is reviewed. All this work has resulted in unprecedented insights into the early stage of nucleation and it is also relevant for a deeper understanding of soft matter materials in general as well as for possible applications based on colloidal suspensions.

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“…Optical trapping techniques are one of the most common methods of creating periodic substrates for colloids [3]. Studies of colloidal ordering and melting for one dimensional (1D) periodic substrate arrays have revealed ordered colloidal crystalline structures as well as smectic type structures where the colloids are crystalline in one direction and liquidlike in the other [4][5][6][7][8][9][10][11][12]. These experiments show that the substrate strength strongly influences the type of colloidal structure that forms and that as the substrate strength increases, the resulting enhancement of fluctuations can induce a transition from crystalline to smectic order [4,6,8].…”

Section: Introductionmentioning

confidence: 99%

Statics and dynamics of Yukawa cluster crystals on ordered substrates

Reichhardt

2012

Phys. Rev. E

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We examine the statics and dynamics of particles with repulsive Yukawa interactions in the presence of a two-dimensional triangular substrate for fillings of up to 12 particles per potential minimum. We term the ordered states Yukawa cluster crystals and show that they are distinct from the colloidal molecular crystal states found at low fillings. As a function of substrate and interaction strength at fixed particle density we find a series of novel crystalline states that we characterize using the structure factor. For fillings greater than four, shell and ring structures form at each potential minimum and can exhibit sample-wide orientational order. A disordered state can appear between ordered states as the substrate strength varies. Under an external drive, the onsets of different orderings produce clear changes in the critical depinning force, including a peak effect phenomenon that has generally only previously been observed in systems with random substrates. We also find a rich variety of dynamic ordering transitions that can be observed via changes in the structure factor and features in the velocity-force curves. The dynamical states encompass a variety of moving structures including one-dimensional stripes, smectic ordering, polycrystalline states, triangular lattices, and symmetry locking states. Despite the complexity of the system, we identify several generic features of the dynamical phase transitions which we map out in a series of phase diagrams. Our results have implications for the structure and depinning of colloids on periodic substrates, vortices in superconductors and Bose-Einstein condensates, Wigner crystals, and dusty plasmas.

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Entropy versus energy: The phase behavior of a hard-disk mixture in a periodic external potential

Cited by 18 publications

References 28 publications

Colloids in light fields: Particle dynamics in random and periodic energy landscapes

Colloids in light fields: Particle dynamics in random and periodic energy landscapes

Crystallization in three- and two-dimensional colloidal suspensions

Statics and dynamics of Yukawa cluster crystals on ordered substrates

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