Spinel-type Al <sub>4</sub> C <sub>3</sub> attainable above 7 GPa and more high-pressure phases of Al <sub>4</sub> C <sub>3</sub>
We predict that Al<sub>4</sub>C<sub>3</sub> adopts a cubic, anti-spinel-type structure (Al<sub>4</sub>C<sub>3</sub>-II) between 7 and 33 GPa, peaking in stability relative to other Al<sub>4</sub>C<sub>3</sub> structures at 26 GPa. At ambient pressure, Al<sub>4</sub>C<sub>3</sub>-II is mechanically robust, with a bulk modulus of 160 GPa and a Vickers hardness of around 30 GPa. Beyond Al<sub>4</sub>C<sub>3</sub>-II, we identify three additional post-spinel phases appearing in the Al<sub>4</sub>C<sub>3</sub> phase diagram, including an anti-Th<sub>3</sub>P<sub>4</sub>-type at 140 GPa. The clear enthalpy differences under pressure leave little doubt that the known trigonal <i>R</i>3̄<i>m</i> ground state of Al<sub>4</sub>C<sub>3</sub> will undergo multiple phase transitions. The accessible pressure window for spinel-type Al<sub>4</sub>C<sub>3</sub>-II is easily accessible in both laser-heated diamond anvil cell and large-volume multi-anvil cell experiments. We therefore encourage experimental exploration of the Al-C system at high pressure.
Authors
- Peter Kroll (ORCID: https://orcid.org/0000-0003-4782-2805)
- Mitchell Falgoust
Institutions
- The University of Texas at Arlington (US)
Publication Details
- Journal
- Chemical Science
- Published
- 2025-12-04
- DOI
- https://doi.org/10.1039/d5sc06382e
- Primary Topic
- Boron and Carbon Nanomaterials Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- University of Texas at Arlington
- Division of Materials Research
- Office of Advanced Cyberinfrastructure