The exotically stoichiometric compounds in Al–S system under high pressure

Abstract

Aluminum and sulfur, as abundant elements in earth, only form Al2S3 in nature at ambient pressure. It has been realized that the stoichiometry of compounds may change under high pressure, which is crucial in the discovery of novel materials. In this work, we systematically perform structure search for Al–S system under pressure. Four binary compounds of Al–S with exotic stoichiometries of AlS, Al2S, Al3S4, and AlS2 are found at high pressure and show exciting physical properties. In particular, Al3S4 becomes a superconductor with a predicted superconducting transition temperature Tc of 20.9 K at 100 GPa, while the pressure-induced Al2S becomes an electride, where the valence electrons of aluminum strongly localize in the interstices, acting as anions, at a pressure of 70 GPa. This work provides a viable direction for further experimental study of the properties of Al–S system.

Ba with Unusual Oxidation States in Ba Chalcogenides under Pressure

“…Then, a new P 4 1 2 1 2 BaS 2 phase emerges to be stable again between 95.3 and 140 GPa. A similar transition has appeared in the Al–S system . For BaS 3 , a structural transition from P -42 1 m to C 2 occurs at 74.7 GPa, remaining stable up to 102.5 GPa.…”

“…A similar transition has appeared in the Al−S system. 55 For BaS 3 , a structural transition from P-42 1 m to C2 occurs at 74.7 GPa, remaining stable up to 102.5 GPa. Third, two new compositions, Ba-rich Ba 3 S 2 and S-rich BaS 4 , are found to be stable at high pressures.…”

Structure and motifs of iron oxides from 1 to 3 TPa

“…These motifs pack in the face-sharing arrangement. This structure is the same as the I4/mmm-type phases of Fe 2 Mg [34] and Al 2 S [35]. The calculated phonon spectrum confirms that this phase is dynamically stable at 1, 2 and 3 TPa with an electron temperature (T el ) of 8000 K as seen in Fig.…”

Electrides: a review

“…79 There are other, varied and interesting compounds that are predicted to be electrides at high pressure. For example, the systems of Al-S, 81 Li-N, 82 Mg-O, 83 Na-Cl, 84 and Li-O, 85 have predicted stable compounds that behave as electrides under sufficient pressure, to name just a few.…”