Phase stability of the nanolaminates V2Ga2C and (Mo1−xVx)2Ga2C from first-principles calculations

Abstract

We here use first-principles calculations to investigate the phase stability of the hypothetical laminated material V₂Ga₂C and the related alloy (Mo_1−xV_x)₂Ga₂C, the latter for a potential parent material for synthesis of (Mo_1−xV_x)₂C, a new two-dimensional material in the family of so called MXenes. We predict that V₂Ga₂C is thermodynamically stable with respect to all identified competing phases in the ternary V–Ga–C phase diagram. We further calculate the stability of ordered and disordered configurations of Mo and V in (Mo_1−xV_x)₂Ga₂C and predict that ordered (Mo_1−xV_x)₂Ga₂C for x ≤ 0.25 is stable, with an order–disorder transition temperature of ∼1000 K. Furthermore, (Mo_1−xV_x)₂Ga₂C for x = 0.5 and x ≥ 0.75 is suggested to be stable, but only for disordered Mo–V configurations, and only at elevated temperatures. We have also investigated the electronic and elastic properties of V₂Ga₂C; the calculated bulk, shear, and Young's modulus are 141, 94, and 230 GPa, respectively.