Thermodynamic and dynamic stability of NaLiC : Exploring superconductivity in a layered hexagonal compound through first-principles calculations

Abstract

The layered hexagonal compound NaLiC4 has been thoroughly investigated to assess its thermodynamic and dynamic stability in comparison to its parent compounds NaC2and LiC2. Utilizing first-principles calculations and phonon analyses, NaLiC4 has demonstrated remarkable stability within a pressure range of 50 to 100 GPa, surpassing the thermodynamic stability of NaC2and LiC2. It exhibits metallic behavior with distinctive electronic bands along high symmetry paths, suggesting a conducive environment for superconductivity. The superconducting transition temperature (Tc) of NaLiC4under different pressures was estimated using the Allen-Dynes equation, with a maximum Tcof 39 K observed at 50 GPa. However, as pressure increases, Tcgradually decreases, indicating the significant impact of external pressure conditions on the superconducting properties. Notably, the in-plane E2gphonon mode originating from the layered hexagonal structure of carbon atoms plays a crucial role in facilitating electron-phonon coupling and influencing the superconducting behavior and Tcof NaLiC4. These findings highlight the thermodynamic and dynamic stability of NaLiC4as a promising candidate for exploring superconductivity, offering insights into its electronic properties, pressure-dependent Tcbehavior, and the influence of specific phonon modes. Further theoretical investigations and experimental studies are necessary to fully unlock the potential of NaLiC4and its contribution to the development of high-performance superconductors