Fivefold twinning in thin films and small particles of nanometer dimensions is the origin of metastable structures the ubiquituous presence of wich in a whole class of nanocrystalline materials results from the great variety of materials and fabrication processes involved. These are reviewed and discussed together with the formation mechanism of such structures and their stability including the role of lattice defects. Various illustrative examples are aimed to emphasise the importance of this phenomenon in the area of nanocrystalline materials.

Full text :PDF (861 kB)( for personal use only)