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  2. Quasicrystal - Wikipedia

    en.wikipedia.org/wiki/Quasicrystal

    The second type, icosahedral quasicrystals, are aperiodic in all directions. Icosahedral quasicrystals have a three dimensional quasiperiodic structure and possess fifteen 2-fold, ten 3-fold and six 5-fold axes in accordance with their icosahedral symmetry. [56] Quasicrystals fall into three groups of different thermal stability: [57]

  3. Paul Steinhardt - Wikipedia

    en.wikipedia.org/wiki/Paul_Steinhardt

    Paul Joseph Steinhardt (born December 25, 1952) is an American theoretical physicist whose principal research is in cosmology and condensed matter physics. He is currently the Albert Einstein Professor in Science at Princeton University, where he is on the faculty of both the Departments of Physics and of Astrophysical Sciences.

  4. Timeline of crystallography - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_crystallography

    1929 - Linus Pauling formulated a set of rules (later called Pauling's rules) to describe the structure of complex ionic crystals. [90] 1929 - William Howard Barnes published the crystal structure of ice. [91] 1930 - Lawrence Bragg assembled the first classification of silicates, describing their structure in terms of grouping of SiO 4 ...

  5. Quasicrystals and Geometry - Wikipedia

    en.wikipedia.org/wiki/Quasicrystals_and_Geometry

    The book is divided into two parts. The first part covers the history of crystallography, the use of X-ray diffraction to study crystal structures through the Bragg peaks formed on their diffraction patterns, and the discovery in the early 1980s of quasicrystals, materials that form Bragg peaks in patterns with five-way symmetry, impossible for a repeating crystal structure.

  6. Crystal - Wikipedia

    en.wikipedia.org/wiki/Crystal

    The International Union of Crystallography has redefined the term "crystal" to include both ordinary periodic crystals and quasicrystals ("any solid having an essentially discrete diffraction diagram" [23]). Quasicrystals, first discovered in 1982, are quite rare in practice.

  7. Hyperuniformity - Wikipedia

    en.wikipedia.org/wiki/Hyperuniformity

    The term hyperuniformity (also independently called super-homogeneity in the context of cosmology [22]) was coined and studied by Salvatore Torquato and Frank Stillinger in a 2003 paper, [1] in which they showed that, among other things, hyperuniformity provides a unified framework to classify and structurally characterize crystals, quasicrystals, and exotic disordered varieties.

  8. Penrose tiling - Wikipedia

    en.wikipedia.org/wiki/Penrose_tiling

    They are quasicrystals: implemented as a physical structure a Penrose tiling will produce diffraction patterns with Bragg peaks and five-fold symmetry, revealing the repeated patterns and fixed orientations of its tiles. [1] The study of these tilings has been important in the understanding of physical materials that also form quasicrystals. [2]

  9. Roger Penrose - Wikipedia

    en.wikipedia.org/wiki/Roger_Penrose

    In 1967, Penrose invented the twistor theory, which maps geometric objects in Minkowski space into the 4-dimensional complex space with the metric signature (2,2). [ 45 ] [ 46 ] Penrose is well known for his 1974 discovery of Penrose tilings , which are formed from two tiles that can only tile the plane nonperiodically, and are the first ...