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Theoretical study of the stability of the tetradymitelike phases of Sb$_2$S$_3$, Bi$_2$S$_3$, and Sb$_2$Se$_3$  E. Lora da Silva
; J. M. Skelton
; P. RodríguezHernández
; A. Muñoz
; M. C. Santos
; D. MartínezGarcía
; R. Vilaplana
; F. J. Manjón
;  Date: 
2 Jun 2022  Abstract:  We report a comparative theoretical study of the extit{Pnma} and
extit{R3m} phases of Sb$_2$S$_3$, Bi$_2$S$_3$, and Sb$_2$Se$_3$ close to
ambient pressure.
Our enthalpy calculations at 0 K show that at ambient pressure the
extit{R3m} (tetradymitelike) phase of Sb$_2$Se$_3$ is energetically more
stable than the extit{Pnma} phase, contrary to what is observed for
Sb$_2$S$_3$ and Bi$_2$S$_3$, and irrespective of the exchangecorrelation
functional employed in the calculations.
The result for Sb$_2$Se$_3$ is in contradiction to experiments where all
three compounds are usually grown in the extit{Pnma} phase.
This result is further confirmed by freeenergy calculations taking into
account the temperature dependence of the unitcell volumes and phonon
frequencies.
Lattice dynamics and elastic tensor calculations further show that both
extit{Pnma} and extit{R3m} phases of Sb$_2$Se$_3$ are dynamically and
mechanically stable at zero applied pressure.
Since these results suggest that the formation of the extit{R3m} phase for
Sb$_2$Se$_3$ should be feasible at close to ambient conditions, we provide a
theoretical crystal structure and simulated Raman and infrared spectra to help
in its identification. We also discuss the results of the two published works
that have claimed to have synthesized tetradymitelike Sb$_2$Se$_3$.
Finally, the stability of the extit{R3m} phase across the three group15
extit{A$_2$X$_3$} sesquichalcogenides is analysed based on their van der
Waals gap and XX inplane geometry.  Source:  arXiv, 2206.01025  Services:  Forum  Review  PDF  Favorites 


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