Ambient-pressure superconductivity above 22 K in hole-doped YB₂

Recent studies of hydrogen-dominant (superhydride) materials, such as LaH 10 , have led to putative discoveries of near-room temperature superconductivity at high pressures, with a superconducting transition temperature ( T c ) of 250 K observed at 170 GPa. While these findings are promising, achieving such high superconductivity requires challenging experimental conditions typically exceeding 100 GPa. In this study, we utilize first-principles calculations and Migdal-Eliashberg theory to examine the superconducting properties of the stable boron-based compound YB 2 at atmospheric pressure, where yttrium and boron atoms form a layered structure. Our results indicate that YB 2 exhibits a T c of 2.14 K at 0 GPa. We find that doping with additional electrons (0-0.3) leads to a monotonic decrease in T c . Conversely, introducing holes significantly enhances T c , raising it to 22.83 K. Although our findings do not surpass the superconducting temperature of the well-known MgB 2 , our doping strategy highlights a method for tuning electron-phonon coupling strength in metal borides. This insight could be valuable for future experimental applications. Overall, this study not only deepens our understanding of YB 2 superconducting properties but also contributes to the ongoing search for high-temperature superconductors.