Compression of silver sulfide: X-ray diffraction measurements and total-energy calculations |
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Authors: | Santamaría-Pérez David Marqués Miriam Chuliá-Jordán Raquel Menendez José M Gomis Oscar Ruiz-Fuertes Javier Sans Juan A Errandonea Daniel Recio José M |
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Institution: | Departamento de Qu??mica F??sica I, Universidad Complutense de Madrid, 28040 Madrid, Spain. dsantamaria@quim.ucm.es |
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Abstract: | Angle-dispersive X-ray diffraction measurements have been performed in acanthite, Ag(2)S, up to 18 GPa in order to investigate its high-pressure structural behavior. They have been complemented by ab initio electronic structure calculations. From our experimental data, we have determined that two different high-pressure phase transitions take place at 5 and 10.5 GPa. The first pressure-induced transition is from the initial anti-PbCl(2)-like monoclinic structure (space group P2(1)/n) to an orthorhombic Ag(2)Se-type structure (space group P2(1)2(1)2(1)). The compressibility of the lattice parameters and the equation of state of both phases have been determined. A second phase transition to a P2(1)/n phase has been found, which is a slight modification of the low-pressure structure (Co(2)Si-related structure). The initial monoclinic phase was fully recovered after decompression. Density functional and, in particular, GGA+U calculations present an overall good agreement with the experimental results in terms of the high-pressure sequence, cell parameters, and their evolution with pressure. |
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