Phosphorus Dimerization in Gallium Phosphide at High Pressure
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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 similar to 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) angstrom 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.
Collaborative access team; Augmented-wave method; Diamond-anvil cell; X-ray-diffraction; Crystal-structure; Black phosphorus; Ab-initio; Group-Iv; Iii-V; Phase
Inorganic Chemistry | Physical Chemistry
Weck, P. F.,
Phosphorus Dimerization in Gallium Phosphide at High Pressure.
Inorganic Chemistry, 57(5),