Crystal Growth and Dislocations

Crystal Dislocations

Crystal dislocations were invisible until the mid-20th century although their presence had been inferred; the atomic and molecular scale dimensions had prevented earlier discovery. Now they are normally known to be just about everywhere, for example, in the softest molecularly-bonded crystals as well as within the hardest covalently-bonded diamonds. The advent of advanced techniques of atomic-s...

Charge-density wave phase-slip in niobium triselenide : dislocations and the growth of an, electronic crystal

The analogy is explored between phase-slip in charge-density wave conductors, which brings about the growth and decay of an electronic crystal, and the processes of growth and plastic flow which occur in conventional crystals. The experimental data on NbSq are re-examined, and new measurements of the voltage Vps needed to produce phase-slip at a given rate presented. It is suggested that Vps is...

Screw dislocations in complex, low symmetry oxides: core structures, energetics, and impact on crystal growth.

Determining the atomic structure and the influence of defects on properties of low symmetry oxides have long been an engineering pursuit. Here, we focus on five thermodynamically reversible monoclinic and orthorhombic polymorphs of dicalcium silicates (Ca2SiO3)-a key cement constituent-as a model system and use atomistic simulations to unravel the interplay between the screw dislocation core en...

Ni2As2O7 pyrochlore nanomaterial: Solid state synthesis, crystal structure determination, crystal phase growth study and physical properties

Nanostructured Ni2As2O7 semiconductor samples were synthesized by a solid state method among As2O3 and Ni(NO3)2.6H2O raw materials at 650 °C (S1) and 750 °C (S2) as reaction temperatures. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and F...

Twisted topological solitons and dislocations in a polymer crystal