Nanotwinned Boron Suboxide (B6O): New Ground State of B6O
Reddy, K. Madhav
Oganov, Artem R.
Goddard III, William A.
StatisticsView Usage Statistics
The full text of the article is available at:
Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as ?-B6O, 2?-B6O, and 4?-B6O), consistent with the recently predicted B6O structure with Cmcm space group (?-B6O) which has an energy 1.1 meV/B6O lower than R-B6O. We report here TEM observations of this ?-B6O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new ?-B6O phase which are compared to R-B6O and 2?-B6O. The lowest stress slip system of ?-B6O is (010)/?001? which transforms ?-B6O to R-B6O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/?110?, leading to icosahedra disintegration and hence amorphous band formation.
|Rights Holder||Nano Letters|