Scientists show growing atom-thin sheets on cones allows control of defects

The Rice lab of theoretical physicist Boris Yakobson and

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colleagues at Oak Ridge National Laboratory are combining theory and experimentation to prove it's possible to give 2-D materials specific defects, especially atomic-scale seams called grain boundaries. These boundaries may be used to enhance the materials' electronic, magnetic, mechanical, catalytic and optical properties.

The key is introducing curvature to the landscape that constrains the way defects propagate. The researchers call this "tilt grain boundary topology," and they achieve it by growing their materials onto a topographically curved substrate—in this case, a cone. The angle of the cone dictates if, what kind and where the boundaries appear.

The research is the subject of a paper in the American Chemical Society journal ACS Nano.

Grain boundaries are the borders that appear in a material where edges meet in a mismatch. These boundaries are a series of defects; for example, when two sheets of hexagonal graphene meet at an angle, the carbon atoms compensate for it by forming nonhexagonal (five- or seven-member) rings.

Read more at: https://phys.org/news/2017-08-scientists-atom-thin-sheets-cones-defects.html#jCp