High-pressure superconducting phase of Li-Ba system

Searching for superconducting Lithium-rich compounds has garnered increasing attention due to their unique structural and electronic feature. In this work, we explore pressure-induced stable Li-abundant barium compound leveraging the advanced crystal structure prediction algorithm coupled with first-principles calculations. We identify several stable Li-Ba compounds at high pressure, including P 2/ c Li 9 Ba, R -3 Li 8 Ba, C 2 Li 2 Ba and Pm -3 m LiBa. Of particular interest is the fact that these phases show intrinsic metallic characteristics with significant contributions from Ba at the Fermi level. Electron-phonon coupling simulations indicates that these predicted phases showcase various superconducting critical temperatures of 7.6 K (Li 9 Ba), 7.4 K (Li 8 Ba), 8.9 K (Li 2 Ba) and 5.4 K (LiBa) at moderate pressure of 50-200 GPa. Notably, some metastable Li-rich compounds exhibit favorable superconductivity with high critical temperatures, such as ~35.6 K for Li 6 Ba at 200 GPa. Our findings provide insights into lithium-bearing systems with implications for pursuing pressure-induced superconductors.