Crystal Structure, Infrared Spectrum and Elastic Anomalies in Tuperssuatsiaite

• Main Authors: Colmenero, Francisco, Sejkora, J., Plášil, J.
• Other Authors: Consejo Superior de Investigaciones Científicas (España), Ministry of Education, Youth and Sports (Czech Republic), Ministry of Culture (Czech Republic)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Nature Publishing Group 2020
• Subjects: Condensed-matter physics; Materials science; Mechanical properties; Structure of solids and liquids; Theory and computation; Greenland
• Online Access: http://hdl.handle.net/10261/221432; https://doi.org/10.1038/s41598-020-64481-8; https://doi.org/10.13039/501100003339

14 pags., 8 figs. The full crystal structure of the phyllosilicate mineral tuperssuatsiaite, including the positions of the hydrogen atoms in its unit cell, is determined for the first time by using first-principles solid-state methods. From the optimized structure, its infrared spectrum and elastic properties are determined. The computed infrared spectrum is in excellent agreement with the experimental spectrum recorded from a natural sample from Ilímaussaq alkaline complex (Greenland, Denmark). The elastic behavior of tuperssuatsiaite is found to be extremely anomalous and significant negative compressibilities are found. Tuperssuatsiaite exhibits the important negative linear compressibility phenomenon under small anisotropic pressures applied in a wide range of orientations of the applied strain and the very infrequent negative area compressibility phenomenon under external isotropic pressures in the range from 1.9 to 2.4 GPa. The anisotropic negative linear compressibility effect in tuperssuatsiaite is related to the increase of the unit cell along the direction perpendicular to the layers charactering its crystal structure. The isotropic negative area compressibility effect, however, is related to the increase of the unit cell dimensions along the directions parallel to the layers. Te supercomputer time provided by the CTI-CSIC center is greatly acknowledged. JP acknowledges the support through the project no. LO1603 of the Ministry of Education, Youth and Sports National Sustainability Program I of the Czech Republic. JS was supported by the Ministry of Culture of the Czech Republic (long-term project DKRVO 2019–2023/1.II.b).