Expanding quasiperiodicity in soft matter: Supramolecular decagonal quasicrystals by binary giant molecule blends

The quasiperiodic structures in metal alloys have been known to depend on the existence of icosahedral order in the melt. Among different phases observed in intermetallics, decagonal quasicrystal (DQC) structures have been identified in many glass-forming alloys yet remain inaccessible in bulk-state condensed soft matters. Via annealing the mixture of two giant molecules, the binary system assemblies into an axial DQC superlattice, which is identified comprehensively with meso-atomic accuracy. Analysis indicates that the DQC superlattice is composed of mesoatoms with an unusually broad volume distribution. The interplays of submesoatomic (molecular) and mesoatomic (supramolecular) local packings are found to play a crucial role in not only the formation of the metastable DQC superlattice but also its transition to dodecagonal quasicrystal and Frank–Kasper σ superlattices.

SUBSTRATE MATERIAL INFLUENCE ON THE THERMOCHEMICAL LASER WRITING OF DIFFRACTIVE STRUCTURES ON ZIRCONIUM FILMS

The paper is devoted to comparing the features of the formation of oxide microstructures during direct laser writing on thin (100 nm) zirconium films deposited on glass and fused silica substrates to identify the most stable and predicted writing modes. The presence of self-induced oxide quasiperiodic structures was detected during continuous laser writing on zirconium films deposited on glass substrates. The effect of the formation of nanostructures, which are parallel cracks in the oxide layer and have a period equal to the recording step (250-500 nm), formed during the writing process on zirconium films deposited on a quartz substrate is revealed. The advantages of fused silica as a substrate material for direct laser writing on zirconium films are shown due to the higher softening temperature of fused silica compared to glass.

Breaking of Internal Waves and Turbulent Dissipation in an Anticyclonic Mode Water Eddy

A 4-month glider mission was analyzed to assess turbulent dissipation in an anticyclonic eddy at the western boundary of the subtropical North Atlantic. The eddy (radius ≈ 60 km) had a core of low potential vorticity between 100 and 450 m, with maximum radial velocities of 0.5 m s−1 and Rossby number ≈ −0.1. Turbulent dissipation was inferred from vertical water velocities derived from the glider flight model. Dissipation was suppressed in the eddy core (ε ≈ 5 × 10−10 W kg−1) and enhanced below it (>10−9 W kg−1). Elevated dissipation was coincident with quasiperiodic structures in the vertical velocity and pressure perturbations, suggesting internal waves as the drivers of dissipation. A heuristic ray-tracing approximation was used to investigate the wave–eddy interactions leading to turbulent dissipation. Ray-tracing simulations were consistent with two types of wave–eddy interactions that may induce dissipation: the trapping of near-inertial wave energy by the eddy’s relative vorticity, or the entry of an internal tide (generated at the nearby continental slope) to a critical layer in the eddy shear. The latter scenario suggests that the intense mesoscale field characterizing the western boundaries of ocean basins might act as a “leaky wall” controlling the propagation of internal tides into the basin’s interior.

Evolution of Quasiperiodic Structures in a Non-Ideal Hydrodynamic Description of Phase Transitions

Various phase transitions could have taken place in the early universe, and may occur in the course of heavy-ion collisions and supernova explosions, in proto-neutron stars, in cold compact stars, and in the condensed matter at terrestrial conditions. Most generally, the dynamics of the density and temperature at first- and second-order phase transitions can be described with the help of the equations of non-ideal hydrodynamics. In the given work, some novel solutions are found describing the evolution of quasiperiodic structures that are formed in the course of the phase transitions. Although this consideration is very general, particular examples of quark-hadron and nuclear liquid-gas first-order phase transitions to the uniform k 0 = 0 state and of a pion-condensate second-order phase transition to a non-uniform k 0 ≠ 0 state in dense baryon matter are considered.

Modeling of quasicrystal lattices with a 4-fold symmetry axis

The construction method of a quasilattice with a four-fold rotational symmetry axis is proposed. The described method is based on the recurrent generation of the initial group of lattice points, which are a set of vertices of a square. The aperiodic crystal reciprocal lattice modeling algorithm is analyzed. Used modeling technique is compared with conventional projection approach. The orthogonal basis of a four-dimensional hypercubic lattice is proposed. This lattice produces two-dimensional quasicrystal with a four-fold symmetry axis after it projection on a flat surface. It is shown that the indexation of diffraction pattern of similar quasiperiodic structures can be carry out using 3 integer indexes, which is analogous to the indexing system proposed by Cahn for application to icosahedral quasicrystals.

Simultaneous localization of photons and phonons in defect-free dodecagonal phoxonic quasicrystals

In dodecagonal phoxonic quasicrytals (PhXQCs) with a very high rotational symmetry, we demonstrate numerically large phoxonic band gaps (PhXBGs, the coexistence of photonic and phononic band gaps). By computing the existence and dependence of PhXBGs on the choice of radius of holes, we find that PhXQCs can possess simultaneous photonic and phononic band gaps over a rather wide range of geometric parameters. Furthermore, localized modes of THz photons and tens of MHz phonons may exist inside and outside band gaps in defect-free PhXQCs. The electromagnetic and elastic field can be confined simultaneously around the quasicrytals center and decay in a length scale of several basic cells. As a kind of quasiperiodic structures, 12-fold PhXQCs provide a good candidate for simultaneously tailoring electromagnetic and elastic waves. Moreover, these structures exhibit some interesting characteristics due to the very high symmetry.