Structural stability of CuAl2O4under pressure
P A Agzamova1,2, A A Belik3, S V Streltsov1,2
1M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia.
Abstract:
Structural properties of CuAl2O4, which was recently argued to show unusual suppression of the Jahn-Teller distortions by the spin-orbit coupling, are investigated under pressures up to 6 GPa. Analysis of x-ray powder diffraction experiments shows that CuAl2O4gets unstable and decomposes onto CuO and Al2O3at pressures ∼6 GPa and temperature ∼1000 K. This finding is complemented by the density-functional theory +U+ spin-orbit coupling calculations, which demonstrate that this instability is partially driven by a (relatively) large compressibility of strongly Jahn-Teller distorted CuO.
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