Open AccessIn-plane ordered quaternary M4/3′M2/3″AlB2 phases (i-MAB): electronic structure and mechanical properties from first-principles calculations
Author(s) -
Hans Lind,
Martin Dahlqvist,
Johanna Rosén
Publication year - 2021
Publication title -
journal of physics. condensed matter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 228
eISSN - 1361-648X
pISSN - 0953-8984
DOI - 10.1088/1361-648x/abf9bc
Subject(s) - materials science , crystallography , electronic structure , density functional theory , thermodynamics , physics , chemistry , condensed matter physics , computational chemistry
We have by means of first principles density functional theory calculations studied the mechanical and electronic properties of the so called i -MAB phases, M 4/3 ′ M ″ 2/3 AlB 2 , where M ′ = Cr, Mo, W and M ″ = Sc, Y. These phases, experimentally verified for Mo 4/3 Sc 2/3 AlB 2 and Mo 4/3 Y 2/3 AlB 2 , display an atomically laminated structure with in-plane chemical order between the M ′ and M ″ elements. Structural properties, along with elastic constants and moduli, are predicted for different structural symmetries, including the reported R 3 ̄ m (#166) space group. We find all considered i -MAB phases to be metallic with a significant peak in the electronic structure at the Fermi level and no significant anisotropy in the electronic band structure. The simulations also indicate that they are rather hard and stiff, in particular the Cr-based ones, with a Young’s modulus E of 325 GPa for M ″ = Sc. The Mo-based phases are similar, with E = 299 GPa for M ″ = Sc, which is higher than the corresponding laminated carbides ( i -MAX phases).