Author(s) Lavina, B.; Kim, E.; Cynn, H.; Weck, P.F.; Seaborg, K.; Siska, E.; Meng, Y.; Evans, W.
Journal Inorg Chem
Date Published 2018 Mar 05
Abstract

Using combined experimental and computational approaches, we show that at 43 GPa and 1300 K gallium phosphide adopts the super- Cmcm structure, here indicated with its Pearson notation oS24. First-principles enthalpy calculations demonstrate that this structure is more thermodynamically stable above ∼20 GPa than previously proposed polymorphs. In contrast to other polymorphs, the oS24 phase shows a strong bonding differentiation and distorted fivefold coordination geometries of both P atoms. The shortest bond of the phase is a single covalent P-P bond measuring 2.171(11) Å at synthesis pressure. Phosphorus dimerization in GaP sheds light on the nature of the super- Cmcm phase and provides critical new insights into the high-pressure polymorphism of octet semiconductors. Bond directionality and anisotropy explain the relatively low symmetry of this high-pressure phase.

DOI 10.1021/acs.inorgchem.7b02478
ISSN 1520-510X
Citation Inorg Chem. 2018;57(5):24322437.

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