Exploring global phase stability of (VN)1/(InN)1 and (CrN)1/(GaN)1 superlattices from density-functional theory

The quest for design half-metallic ferromagnets superlattice (HMFS) materials has captivated marked attention due to their potential applications in spin-based electronics. Unfortunately, the HMFS proposal still questionable if the stability of such compound is not satisfied. Herein, the importance of the global phase stability of half-metallic ferromagnets (VN)1/(InN)1 and (CrN)1/(GaN)1 superlattices is explored via ab-initio pseudopotential density-functional theory. We find that (i) the computed negative values of the formation enthalpy indicate that these superlattices are at least metastable. (ii) The calculated elastic constants and phonon dispersion curves evince the respective mechanical and dynamical stability of (VN)1/(InN)1 and (CrN)1/(GaN)1 superlattices. (iii) For moderate temperature (T > 400-450 K), the positive vibrational entropy and negative free energy of vibration enhances thermodynamic stability of (VN)1/(InN)1 and (CrN)1/(GaN)1 superlattices. Our general global phase stability for the specific superlattices investigated evidence credible experimental feasibilities.