Melting of 2D liquid crystal colloidal structure
نویسندگان
چکیده
Using video microscopy, we investigated melting of a two-dimensional colloidal system, formed by glycerol droplets at the free surface of a nematic liquid crystalline layer. Analyzing different structure correlation functions, we conclude that melting occurs through an intermediate hexatic phase, as predicted by the KosterlitzThouless-Halperin-Nelson-Young(KTHNY) theory. However, the temperature range of the intermediate phase is rather narrow, . 1C, and the characteristic critical power law decays of the correlation functions are not fully developed. We conclude that the melting of our 2D systems qualitatively occurs according to KTHNY, although quantitative details of the transition scenario may partly depend on the details of interparticle interaction.
منابع مشابه
Direct observation of melting in a two-dimensional driven granular system.
Melting is considered to be one of the most fundamental problems in physical science. Generally, dimensionality plays an important role in melting. In three-dimension, it's well known that a crystal melts directly into a liquid via a first-order transition. In two-dimension (2D), however, the melting process has been widely debated whether it is a first-order transition or a two-step transition...
متن کاملComparison of 2D melting criteria in a colloidal system.
We use super-paramagnetic spherical particles which are arranged in a two-dimensional monolayer at a water/air interface to investigate the crystal to liquid phase transition. According to the KTHNY theory a crystal melts in thermal equilibrium by two continuous phase transitions into the isotropic liquid state with an intermediate phase, commonly known as the hexatic phase. We verify the signi...
متن کاملTwo-Stage Melting of Paramagnetic Colloidal Crystals in Two Dimensions
A novel two-dimensional system of colloidal particles with absolutely calibrated magnetic interaction is used to investigate static and dynamic properties at the 2D crystal to liquid phase transition. We observe two successive transitions from the solid to the liquid phase with an intermediate hexatic phase, in perfect agreement with the theory of Kosterlitz and Thouless. The absolute values of...
متن کاملThe softening of two-dimensional colloidal crystals
According to the Kosterlitz–Thouless–Halperin–Nelson–Young (KTHNY) theory a two-dimensional (2D) crystal melts when bound pairs of dislocations dissociate into single dislocations. The temperature at which dislocation pairs unbind can be identified by means of the Young’s modulus K passing through 16π . In a previous paper (von Grünberg et al 2004 Phys. Rev. Lett. 93 255703) we analysed video-m...
متن کاملMelting of colloidal crystal films.
We study melting mechanisms in single and polycrystalline colloidal films composed of diameter-tunable microgel spheres with short-ranged repulsive interactions and confined between two glass walls. Thick films (>4 layers), thin-films (≤4 layers), and monolayers exhibit different melting behaviors. Thick films melt from grain boundaries in polycrystalline solid films and from film-wall interfac...
متن کامل