RETRACTED: The bonding, charge distribution, spin ordering, optical, and elastic properties of four MAX phases Cr2AX (A=Al or Ge, X=C or N): From density functional theory study (Retracted article. See vol. 115, 109901, 2014)

In this work, we assess a full spectrum of properties (chemical bonding, charge distribution, spin ordering, optical, and elastic properties) of Cr(2)AC (A = Al, Ge) and their hypothetical nitride counterparts Cr(2)AN (A = Al, Ge) based on density functional theory calculations. The calculated total energy values indicate that a variety of spin ordering of these four compounds depending on interlayer-interactions between M-A and M-X within the sublattice, which is supported by bonding analysis. MAX phase materials are discovered to possess exotic magnetic properties which indicates that these materials could serve as promising candidates for novel layered magnetic materials for various electronic and spintronic applications. Further analysis of optical properties for two polarization vectors of Cr(2)AX shows that the reflectivity is high in the visible-ultraviolet region up to similar to 15 eV suggesting Cr(2)AX as a promising candidate for use as a coating material. The elastic coefficients (C-ij) and bulk mechanical properties [bulk modulus (K), shear modulus (G), Young's modulus (E), Poisson's ratio (eta), and Pugh ratio (G/K)] of these four Cr(2)AX compounds are also calculated and analyzed, which pave the way to predict or design new MAX phases that are less brittle or tougher by having a lower G/K value or higher eta. (C) 2013 AIP Publishing LLC.