울산대학교 | 미래혁신응집물질물리인재교육연구단

Computational predictions of stable phase for antiperovskite Na 3OCl via tilting of Na 6O octahedra
작성자	김**	작성일	2019-07-29	조회수	111
Journal Article published 28 Oct 2018 in Journal of Applied Physics volume 124 issue 16 on page 164106 Research funded by University of Ulsan (2016-0082) Authors: Tan-Lien Pham, Abdus Samad, Hye Jung Kim, Young-Han Shin https://doi.org/10.1063/1.5047833 Abstract We study the structural stability of crystalline Na $_{3}$ OCl in terms of cohesive energies and phonon spectra through the tilting of Na $_{6}$ O octahedra. We prove that the crystal Na $_{3}$ OCl can be stabilized through octahedral tilts by comparing 14 tilted structures that are consistent with the Howard and Stokes’ group-theoretical analysis of the octahedral tilting in perovskites. We found that all the 14 tilted structures of Na $_{3}$ OCl have lower energies than the cubic Pm $\bar{3}$ m structure by about 11 to 16?meV per five-atom unit cell. The tilt angles along the pseudocubic [100], [010], and [001] directions vary in the range of 2.6 $^{°}$ ?9.3 $^{°}$ . While the Pnma and P2 $_{1}$ /m structures of Na $_{3}$ OCl are found as the two most stable ones, only the P2 $_{1}$ /m phase has stable phonon vibrations with a direct band gap of 3.38?eV at the $Γ$ point.

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