Theoretical and Experimental Investigations into Novel Oxynitride Discovery in the GaN-TiO2 System at High Pressure
AbstractWe employed ab initio evolutionary algorithm USPEX to speed up the discovery of a novel oxynitride in the binary system of GaN-TiO2 using high-pressure synthesis. A 1:2 mixture of GaN and nanocrystalline TiO2 (anatase) was reacted under 1 GPa of pressure and at 1200 °C in a piston cylinder apparatus to produce a mixture of TiO2 (rutile) and an unknown phase. From the initial analysis of high resolution neutron and X-ray diffraction data, it is isomorphic with monoclinic V2GaO5 with a unit cell composition of Ga10Ti8O28N2 with the following parameters: monoclinic, space group C2/m, a = 17.823(1) Å, b = 2.9970(1) Å, c = 9.4205(5) Å, β = 98.446(3)°; Volume = 497.74(3) Å3. Further, a joint rietveld refinement revealed two distinct regimes—A Ti-rich block and a Ga-rich block. The Ti-rich block consists of four edge-shared octahedra and contains a site which is about 60% occupied by N; this site is bonded to four Ti. The remainder of the block consists of edge linked Ti-octahedral chains linked to the TiN/TiO fragments at octahedral corners partially occupied by nitrogen. The Ga-block contains two symmetry independent octahedral sites, occupied mostly by Ga, and a pure Ga-centered tetrahedral site bonded mostly to oxygen. View Full-Text
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James, A.; Esfahani, M.M.D.; Woerner, W.R.; Sinclair, A.; Ehm, L.; Oganov, A.R.; Parise, J.B. Theoretical and Experimental Investigations into Novel Oxynitride Discovery in the GaN-TiO2 System at High Pressure. Crystals 2018, 8, 15.
James A, Esfahani MMD, Woerner WR, Sinclair A, Ehm L, Oganov AR, Parise JB. Theoretical and Experimental Investigations into Novel Oxynitride Discovery in the GaN-TiO2 System at High Pressure. Crystals. 2018; 8(2):15.Chicago/Turabian Style
James, Alwin; Esfahani, M. M.D.; Woerner, William R.; Sinclair, Alexandra; Ehm, Lars; Oganov, Artem R.; Parise, John B. 2018. "Theoretical and Experimental Investigations into Novel Oxynitride Discovery in the GaN-TiO2 System at High Pressure." Crystals 8, no. 2: 15.
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