Growth mechanism of a long-range ordered quasicrystal in molecular dynamics simulations

The mechanism of a quasicrystal (QC) growth, that is, the mechanism by which long-range quasicrystalline order (LRQO) is generated via growth, is investigated using Engel's model and molecular dynamics simulations. At high temperatures, LRQO is generated, while at low temperatures it is not. During growth at high temperatures, the QC structure near the growth front is highly phason-disordered, and subsequently, in the bulk, this undergoes phason relaxation. Here, phason relaxation is fast, hence phason fluctuation does not increase with QC growth, resulting in the LRQO formation. Phason relaxation times previously evaluated experimentally for QC alloys suggest that similar mechanism should work in the growth of real QC alloys. Such mechanisms involving phason relaxation have rarely been considered in previous growth models of QC alloys. (author)