Artificially layered materials are ideal model systems to tune the dimensionality of the superconducting order as well as the structure of the flux line lattice. Our extensive studies of Pb/Ge multilayers indicate that the anisotropy of the upper critical field H,, strongly depends on the Ge separator thickness d,, . The dimensional crossover from D = 3 towards D = 2, which is revealed by an up...

We study various families of two-dimensional discrete or lattice solitons, and show that they are possible only when their power level exceeds a critical threshold. In addition, we show that gap-lattice solitons exist only when the lattice possesses a complete 2D band gap. Our results suggest that these conditions are universally valid, irrespective of the nature of the nonlinearity or the spec...

In this note, we study the lattice structure on the class of all weak hyper K-ideals of a hyper K-algebra. We first introduce the notion of (left,right) scalar in a hyper K-algebra which help us to characterize the weak hyper K-ideals generated by a subset. In the sequel, using the notion of a closure operator, we study the lattice of all weak hyper K-ideals of ahyper K-algebra, and we prove a ...

The cluster representation matrices have already been successfully used to enumerate close-packed vacancy clusters in all single-lattice crystals [I, 2]. Point defect clusters in double-lattice crystals may have identical geometry but are distinct due to unique atomic postions enclosing them. The method of representation matrices is extended to make it applicable to represent and enumerate ...

We consider a simple model consisting of particles with four bonding sites ("patches"), two of type A and two of type B, on the square lattice, and investigate its global phase behavior by simulations and theory. We set the interaction between B patches to zero and calculate the phase diagram as the ratio between the AB and the AA interactions, ε(AB)*, varies. In line with previous work, on thr...

The aim of the present study is to demonstrate how mesoporous nanostructures of Zinc Sulfide (ZnS) will precipitate in an ethanol media in spite of negligible solubility of Sodium Nitrate (Na2S), which is role-played as sulfur precursor. On the following, the role of such synthesizing method on the photocatalytic behavior of ZnS mesoporous nanostructures has been investigated. Characterization ...

The degree of charge transfer and the upper critical field of the organic superconductor ~MDT-TSF!(AuI2)x have been investigated ~MDT-TSF: methylenedithio-tetraselenafulvalene!. The x-ray oscillation photograph indicates that the anion lattice is incommensurate with the donor lattice, and the chemical composition is ~MDT-TSF!(AuI2)0.44 . The charge-transfer degree of this salt is 0.44. The elec...

Using numerical techniques and asymptotic expansions we obtain the phase diagram of a paradigmatic model of Coulomb-frustrated phase separation in systems with negative short-range compressibility. The transition from the homogeneous phase to the inhomogeneous phase is generically first order in isotropic three-dimensional systems except for a critical point. Close to the critical point, inhomo...

the cluster representation matrices have already been successfully used to enumerate close-packed vacancy clusters in all single-lattice crystals [i, 2]. point defect clusters in double-lattice crystals may have identical geometry but are distinct due to unique atomic postions enclosing them. the method of representation matrices is extended to make it applicable to represent and enumerate the ...