Unified and ultimate high-pressure phase of several nanolaminate Mn+1AXn (n = 1, 2, 3, etc.) ceramics from first principles

Abstract

We did extensive research for the nanolaminate Mn+1AXn (n = 1, 2, 3, etc.) ceramics on their structural stability, in which the “M”, “A” and “X” dependence of the phase transition pressure is concluded. Mo2GaC presents multi-phase co-existence status at high pressure. The hexagonal P63/mmc to tetragonal P4/mmm transition is the common direct route for the N-containing MAX due probably to the high transition pressure. P63/mmc (No.194, α, β) α → β → P4/mmm transition might be the common route for the C-containing MAX due probably to the low α → β transition pressure. Nb2InN/Nb2GaN and Mo2InN present c-axis abnormal elongation at low pressures.

Keywords

• Mn+1AXn
• Phase transition
• First principles