Prediction of Ambient-Pressure High-Temperature Superconductivity in Doped Transition-Metal Hydrides

The search for conventional superconductors with high transition temperatures ($T_c$) has largely focused on intrinsically metallic compounds. In this work, we explore the potential of intrinsically non-metallic compounds to exhibit high-$T_c$ superconductivity under ambient pressure through carrier doping. We identify $\rm MgAlFeH_6$, a representative of carrier-doped transition-metal hydrides like $\rm Mg_2FeH_6$, as a promising example with a predicted $T_c \approx 130~\rm K$. We propose that the average projected electron density of states, defined as the geometric mean of the total and hydrogen-projected density of states at the Fermi level, serves as a simple and computationally inexpensive indicator of high-$T_c$ behavior. We also highlight the tradeoff between high-$T_c$ and dynamic stability, both of which depend on the electron density of states. Our findings thus expand the pool of potential superconducting materials and offer a practical route for accelerating the discovery of superconductors suitable for real-world applications.