Showing posts with label crystals. Show all posts
Showing posts with label crystals. Show all posts

Friday, May 6, 2011

Physics: atomic-scale surface imaging ushered nanotechnology: physics.aps.org

Physics - Proper carbon ID required:
"The ability to image surfaces with atomic-scale resolution in the 1980s ushered in the nanotechnology era. From the beginning, it was understood that although scanning tunneling microscopy (STM) could resolve distances between individual atoms on surfaces, what the images really showed were spatial variations in the electronic density of states of the surface near the Fermi level"


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Thursday, May 5, 2011

Valleytronics one step closer to reality | e! Science News

NRL researchers take a step toward valleytronics | e! Science News:

This image shows an extended line defect in graphene.The band structure of graphene with its two valleys is shown in blue and red.

The valley degree of freedom in graphene gained attention in 2007 when it was proposed that electrons and holes could be filtered according to which valley they occupy. Unfortunately, the structures required for this and subsequent valley filters are difficult to fabricate, and as a result a valley filter has yet to be demonstrated experimentally

"Valley refers to energy depressions in the band structure, which describes the energies of electron waves allowed by the symmetry of the crystal."


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Liquid crystals: cholesteric blue - Discovery of new ordered structures (nanoweek.com)

Discovery of new ordered structures of a liquid crystal:
Schematic illustrations of isotropic, nematic, and cholesteric blue phases
"Liquid crystals are widely used in various devices including TV displays and cellular phone displays due to their unique optical properties that can be easily controled. Most of such devices utilize the change in the optical properties of a nematic phase (a phase of liquid crystals in which molecules align in one direction) by applying an electric field. Recently, different types of ordered phases of liquid crystals referred to as cholesteric blue phases"

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Friday, March 25, 2011

Honeycomb crystalline structure & quantum dots

Silicene: It Could Be The New Graphene - Science News:
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"Speaking March 24 at a meeting in Dallas of the American Physical Society, Fleurence described a new recipe for making silicene. He and his Japanese colleagues grew a thin layer of silicon on top of the ceramic material zirconium diboride. X-rays shined on this thin layer of silicon revealed a honeycomb of hexagons similar to the structure of graphene."

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