Prediction of ambient-pressure high-temperature superconductivity in electronically modified transition-metal hydrides

Abstract The search for conventional superconductors with high transition temperatures (T₂ T c) has largely focused on intrinsically metallic compounds. In this work, we explore the potential of intrinsically non-metallic compounds to exhibit high- T₂ T c superconductivity under ambient pressure through carrier doping. We identify MgAlFeH 6, a representative of carrier-doped transition-metal hydrides like Mg 2 FeH 6, as a promising example with a predicted T₂ 130\, K T c ≈ 130 K. We propose that the average projected electron density of states (DOS), defined as the geometric mean of the total and hydrogen-projected DOS at the Fermi level, serves as a simple and computationally inexpensive indicator of high- T₂ T c behavior. Notably, the correlation between T₂ T c and the average projected DOS is stronger than that between T₂ T c and either total DOS or hydrogen-projected DOS. We also highlight the tradeoff between high- T₂ T c and dynamic stability, both of which depend on the electron DOS at the Fermi level. 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.