English

Diamond Twin

Metric Geometry 2019-05-28 v2

Abstract

As noticed in 2006 by the author of the present article, the hypothetical crystal---described by crystallographer F. Laves (1932) for the first time and designated ``Laves' graph of girth ten" by geometer H. S. M. Coxeter (1955)---is a unique crystal net sharing a remarkable symmetric property with the diamond crystal, thus deserving to be called the diamond twin although their shapes look quite a bit different at first sight. In this short note, we shall provide an interesting mutual relationship between them, expressed in terms of ``building blocks" and ``period lattices." This may give further justification to employ the word ``twin." What is more, our discussion brings us to the notion of ``orthogonally symmetric lattice," a generalization of irreducible root lattices, which makes the diamond and its twin very distinct among all crystal structures.

Cite

@article{arxiv.1904.07230,
  title  = {Diamond Twin},
  author = {Toshikazu Sunada},
  journal= {arXiv preprint arXiv:1904.07230},
  year   = {2019}
}

Comments

22 pages, 17 figures

R2 v1 2026-06-23T08:40:13.671Z