Analogous to perovskites, the antiperovskites are also one of the most commonly explored materials in recent years. Antiperovskites received huge attention due to their remarkable properties such as superconductivity, topological property, spin glass behavior, barocaloric effect, magnetoresistance, thermoelectric, magnetostriction, negative thermal expansion, and piezomagnetism. In particular, our motivation is to perform high throughput screening originated from the intriguing magnetic properties of antiperovskites. The main objective of this work is to predict novel magnetic antiperovskites and validate the stability of existing antiperovskites. To our best knowledge this is the first high throughput screening of antiperovskites. In this work, we systematically carried out high throughput screening on 630 magnetic antiperovskites systems by using first-principles calculations to evaluate the stability.

We considered the cubic phase of antiperovskites with the chemical formula M₃AX (M = Cr, Mn, Fe, Co, and Ni; Z = C, N) in the Pm-3m space group. To establish the stability, we considered the following stability criteria: (a) thermodynamic, (b) mechanical, and (c) dynamical stabilities, which have been examined by evaluating the formation energy together with the distance to the convex hull, elastic constants, and phonon dispersions, respectively. The distance from the convex hull is evaluated by considering all possible decompositions into binary and ternary compounds available from experiments or the Materials Project database. Finally based on our screening strategy, we predicted 11 novel antiperovskites which satisfy all the above mentioned stability criteria. Therefore these novel antiperovskites have great chances of being experimentally synthesized and we hope our work will stimulate more investigation on this class of materials.

MAX-phases are ternary compounds with the chemical formula M_n+1AX_n where M is an early transition metal, A an A-group element, and X carbon or nitrogen, with n usually one, two, or three. Due to the combination of metallic and ceramic properties, MAX-phases have been of great interest over the last two decades. MAX-phases exhibit ceramic properties like high stiffness, high chemical resistance, and low thermal expansion coefficients, as well as metallic properties like good thermal and electrical conductivity, high damage tolerance, and good machinability. MAX-phases have a nanolaminated layered structure where covalent M-X layers are separated by monoatomic A-layers. Magnetic MAX-phases have drawn intensive attention recently as the nanolaminated structure supports magnetic ordering between the M-atoms which is of great interest for spintronic applications like MRAMs. We aim at predicting new unsynthesized magnetic MAX-phases by performing DFT calculations. For the prediction of stable MAX-phases we consider thermodynamic, mechanical, and dynamical stability. As thermodynamic stability we consider the stability against the decomposition of the phase into competing phases, e.g., binaries and ternaries. In order to consider all competing phases, we calculate the convex hull for each ternary system investigated which contains all known unary, binary and ternary compounds. From the calculation of the convex hull we obtain the ternary phase diagram of the system which is representatively shown for the Ti-Al-C system. For the mechanical stability the calculated elastic constants have to fulfill the Born stability conditions and dynamic stability is achieved, when the phonon dispersion does not exhibit imaginary modes. Overall, we calculate 47 of 48 synthesized MAX-phases to be stable in order to validate our calculations and predict 16 yet unsynthesized MAX-phases which have a magnetic 3d transition metal as M-element to be stable. For a deeper understanding of our predictions, we perform crystal orbitalHamilton population (COHP) calculations to investigate whether the interatomic interactions are of bonding or anti-bonding nature.