An international team of researchers has discovered a new type of defect in an unconventional material known as a quasicrystal. Mysterious nanodomains observed on the surfaces of quasicrystals led to the discovery. Quasicrystals were already known to have a unique defect type, known as a phason flip, which can form at the surface. The new defect type is related, but unlike the phason flip is not restricted to the surface; it bridges the surface and the bulk. The new defect type serves to balance competing energetic issues and enables higher-energy transition-metal-rich surfaces to be exposed rather than the expected lower-energy aluminum-rich surfaces. If it saves more energy to make the nanodomains than it costs to form higher-energy surfaces and interfaces, then nanodomains are observed. The relationship between surface and bulk defects may be a key to understanding why nanostructures are often unusually strong.
- T. Duguet, B. Ünal, J. Ledieu, J. M. Dubois, V. Fournée and P. Thiel Nanodomains due to Phason Defects at a Quasicrystal Surface. Physical Review Letters, 2011, 106, 076101. DOI: 10.1103/PhysRevLett.106.076101