We propose that the concept of liquids characterized by a given locally preferred structure (LPS) could help in understanding the observed phenomenon of polyamorphism. “True polyamorphism” would involve the competition between two (or more) distinct LPS, one favored at low pressure because of its low energy and one favored at high pressure because of its small specific volume, as in tetrahedral...

We report the holographic fabrication of designed defect lines in photonic crystal lattices through phase engineering using a spatial light modulator (SLM). The diffracted beams from the SLM not only carry the defect’s content but also the defect related phase-shifting information. The phase-shifting induced lattice shifting in photonic lattices around the defects in three-beam interference is ...

In this work, a defect based photonic crystal (PC) structure presented for design of tunable infrared photodetector. Absorption response was investigated under the effects of various structural parameters. Using straight transfer matrix method, PC band edge effect was studied on absorption and a significant absorption enhancement up to %96 was achieved for defect-based structure.

Infrared photodetectors with spectrally selective response are highly desirable for applications such as hyper-spectral imaging and gas sensing. Owing to the ability of photonic density of states modification and dispersion engineering, photonic crystals appear to be one of the most promising platforms for infrared photodetectors with spectrally-selective absorption enhancement. We report here ...

In this work, we explore the possibility of designing photonic crystals to act as magnetic metamaterials: structures that exhibit magnetic properties despite the nonmagnetic character of their constituents. The building blocks of a magnetic material are microscopic magnetic dipoles, and to create a synthetic analog we employ point-defect modes in a photonic crystal. We begin by identifying a po...

Structural Entities in Complex Oxides While materials at low temperatures are often characterized in terms of crystal chemical concepts, descriptions of their high-temperature properties are usually based on defect chemistry. Both approaches are obviously of great value but also have clear limitations. While the defect chemistry is often weakly linked to the crystal structure of the material an...

It is shown that the force on a lattice defect in an elastic body is, like the force on a disclination in a nematic liquid crystal, a real force which, for equilibrium, must be balanced by an external force applied to the closed surface enclosing the defect.

Texture formation in a binary mixture of a flexible polymer and a liquid crystal has been studied using a nonlocal kinetic model for phase separation in the presence of liquid crystalline order. The model takes into account couplings between phase separation, phase ordering, and texture formation. The phase separation-phase ordering coupling leads to orientation normal to local concentration gr...

Atomic defects in crystalline structures have pronounced affects on their bulk properties. Aberration-corrected transmission electron microscopy has proved to be a powerful characterization tool for understanding the bonding structure of defects in materials. In this article, recent results on the characterization of defect structures in two dimensional materials are discussed. The dynamic beha...

Two examples of the director structure and electric field in patterned electrode liquid crystal cells are studied using a recently developed calculational model. First, a display cell that exhibits a homeotropic to multidomainlike transition with twist wall structures has been considered for a liquid crystal with positive dielectric anisotropy. The model elucidates the behavior of the electric ...