Electrical discharge triggers quasicrystal formation in an eolian dune.

Bindi, Luca; Pasek, Matthew A; Ma, Chi; Hu, Jinping; Cheng, Guangming; Yao, Nan; Asimow, Paul D; Steinhardt, Paul J · Proc Natl Acad Sci U S A · 2023

basic_science · Level V

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Abstract

We report the discovery of a dodecagonal quasicrystal Mn<sub>72.3</sub>Si<sub>15.6</sub>Cr<sub>9.7</sub>Al<sub>1.8</sub>Ni<sub>0.6</sub>-composed of a periodic stacking of atomic planes with quasiperiodic translational order and 12-fold symmetry along the two directions perpendicular to the planes-accidentally formed by an electrical discharge event in an eolian dune in the Sand Hills near Hyannis, Nebraska, United States. The quasicrystal, coexisting with a cubic crystalline phase with composition Mn<sub>68.9</sub>Si<sub>19.9</sub>Ni<sub>7.6</sub>Cr<sub>2.2</sub>Al<sub>1.4</sub>, was found in a fulgurite consisting predominantly of fused and melted sand along with traces of melted conductor metal from a nearby downed power line. The fulgurite may have been created by a lightning strike that combined sand with material from downed power line or from electrical discharges from the downed power line alone. Extreme temperatures of at least 1,710 °C were reached, as indicated by the presence of SiO<sub>2</sub> glass in the sample. The dodecagonal quasicrystal is an example of a quasicrystal of any kind formed by electrical discharge, suggesting other places to search for quasicrystals on Earth or in space and for synthesizing them in the laboratory.