High-Pressure Mg3Cl7 Synthesized in a Diamond Anvil Cell as a Polar Metal with Second-Harmonic Generation
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-09-02 |
| Journal | Journal of the American Chemical Society |
| Authors | Yuqing Yin, Leonid Dubrovinsky, Ferenc TasnƔdi, Igor A. Abrikosov, Andrey Aslandukov |
| Institutions | University of Edinburgh, Linkƶping University |
Abstract
Section titled āAbstractāPolar metals have attracted growing interest due to both their significance in fundamental science and their potential functionalities. Here, we report the discovery of a novel polar metal, magnesium chloride Mg<sub>3</sub>Cl<sub>7</sub>, in which the metallicity of the polar structure is uniquely driven by attractive halogen interactions. Mg<sub>3</sub>Cl<sub>7</sub> was synthesized in laser-heated diamond anvil cells and observed at pressures of 28(2)-93(3) GPa. Synchrotron single-crystal X-ray diffraction revealed that the structure of the new compound has polar hexagonal space group <i>P</i>6<sub>3</sub><i>mc</i>, representing an example of a previously unknown <i>anti</i>-Th<sub>7</sub>Fe<sub>3</sub> structure type. Measurements of the physical properties have shown that the material is a metallic conductor capable of emitting second-harmonic generation light. <i>Ab initio</i> calculations support experimental findings and reveal complex halogen-halogen interactions, anionic metallicity, anisotropic electronic structure, and the presence of Dirac and Weyl points at the Fermi level. Our findings broaden the family of polar metals, provide new insight into halogen bonding under extreme conditions, and offer a platform for further exploration of materialsā unconventional electronic behavior.