High-throughput discovery and electron-doping tuning of superconducting ternary lithium borides

Incorporating another metal into binary metal borides has emerged as a highly effective strategy for optimizing material properties. Herein, using high-throughput calculations, we systematically investigated the structural, electronic, and superconducting properties of $Fm\overline{3}m$ and $F\overline{4}3m$ phases of Li₂MB (M = alkaline earth, 3d, and 4d metals). Our analysis of 48 Li₂MB compounds at 0–60 GPa reveals that four of them are promising superconductors with T_C ≥ 10 K. It is further demonstrated that substitution of different M elements serves as an effective strategy for electron doping, enabling precise control of the band structure and density of states near the Fermi level for the $F\overline{4}3m$ phase. This behavior is exemplified in Li₂Sc_1−xTi_xB (x = 0.05–0.25), which transforms from a semiconductor into a metal and further into a superconductor with increasing Ti doping concentration. For the $Fm\overline{3}m$ phase, Dirac points near the Fermi level are observed in the M = Sc and Y systems, suggesting unique electronic behavior. Our work provides deep insight into the superconducting mechanisms of lithium-based borides and offers guidance for the targeted design of novel boride superconductors.