Lind Hans, Dahlqvist Martin, Rosen Johanna
Thin Films Physics, Department of Physics, Chemistry, and Biology, Linköping University, SE-581-83 Linköping, Sweden.
J Phys Condens Matter. 2021 May 21;33(25). doi: 10.1088/1361-648X/abf9bc.
We have by means of first principles density functional theory calculations studied the mechanical and electronic properties of the so called-MAB phases,'″AlB, where' = Cr, Mo, W and″ = Sc, Y. These phases, experimentally verified for MoScAlBand MoYAlB, display an atomically laminated structure with in-plane chemical order between the' and″ elements. Structural properties, along with elastic constants and moduli, are predicted for different structural symmetries, including the reportedR3̄m(#166) space group. We find all considered-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 modulusof 325 GPa for″ = Sc. The Mo-based phases are similar, with= 299 GPa for″ = Sc, which is higher than the corresponding laminated carbides (-MAX phases).
我们通过第一性原理密度泛函理论计算研究了所谓的-MAB相，即′AlB，其中′=Cr、Mo、W，″=Sc、Y的力学和电子性质。这些相在实验上已在MoScAlB和MoYAlB中得到验证，呈现出原子层状结构，′和″元素之间存在面内化学有序性。针对不同的结构对称性，包括已报道的R3̄m（#166）空间群，预测了其结构性质以及弹性常数和模量。我们发现所有考虑的-MAB相都是金属性的，在费米能级处的电子结构中有一个显著的峰值，并且在电子能带结构中没有明显的各向异性。模拟还表明它们相当坚硬且刚性较大，特别是基于Cr的相，当″=Sc时杨氏模量为325 GPa。基于Mo的相类似，当″=Sc时为299 GPa，高于相应的层状碳化物（-MAX相）。
