The world’s first successful production of a three-dimensional structure for quasicrystals formed from a single element was achieved through joint research by Assistant Professor Kazuki Nozawa and Professor Yasushi Ishii of the Chuo University Faculty of Science and Engineering (Department of Physics), Chief Researcher Masahiko Shimoda of the National Institute for Materials Science, Professor Tsai An-Pang of the Tohoku University Institute of Multidisciplinary Research for Advanced Materials, and Professor H.R. Sharma of the University of Liverpool.

Quasicrystals were discovered in 1984 by researchers led by Dr. D. Shechtman (awarded the Nobel Prize in Chemistry in 2011). Currently, more than 100 types of alloys, macromolecules and nanoparticle systems have been discovered. However, researchers have yet to discover a quasicrystal formed from a single element. Quasicrystals are known for their beautiful crystalline structure which is called quasi-periodic and is closely related to the golden ratio. The crystalline structure of quasicrystals is formed from a pentagonal or decagonal atomic arrangement which is not found in normal periodic crystals. The complexity of this structure and the chemical composition has made it difficult to clarify many aspects of quasicrystals. For example the mechanism for stabilizing the quasi-periodic structure and new properties which reflect the unique crystalline structure remain a mystery. For the reasons discussed above, researchers have long searched for a chemically pure quasicrystal formed from a single element. In the current joint research, researchers evaporated lead atoms in the quasicrystal substrate of an existing alloy composed of silver (Ag), -indium (In) and ytterbium (Yb). As a result, researchers succeeded in growing a crystal for lead with a quasi-periodic structure modeled on the structure of substrate quasicrystal. Previously, there were reports of research which used a similar method to realize a single-element quasi-period film of 1 atomic layer (two-dimensional). However, the current research marks the first successful production of a single-element quasicrystal structure formed from multiple atomic layers (three-dimensional). These results are a major step towards the realization of a single-element quasicrystal. Moreover, the research is expected to lead to advancements in a variety of areas, including the discovery of unique quasi-periodic physical structures which do not exist in periodic crystals and clarification of the expression mechanism for quasi-periodic structures.

[Magazine publishing the research]
Nature Communications, 4, 2715(2013), DOI: 10.1038/ncomms3715,
Published in the November 4th edition.

Please refer to the following links for further details.

• Detailed Material (PDF: 677KB)
• Condensed Matter Theory Group (Ishii Laboratory)