3D Topological Inorganic Electrides: Screening, Properties, and Applications.

The convergence of inorganic electrides and topological quantum phenomena has ushered in novel paradigms for designing advanced quantum materials. While low-dimensional (0-2D) topological inorganic electrides have garnered considerable attention, their three-dimensional (3D) counterparts-featuring intricate interstitial electron networks-remain entirely uncharted territory. Herein, the identification of twelve 3D inorganic electrides within the rare-earth hydride family is reported, nine of which are previously unreported. First-principles calculations reveal a diverse magnetic landscape: two systems exhibit ferromagnetic ordering, while seven demonstrate antiferromagnetic configurations. Strikingly, these materials host rich topological states, encompassing nodal points, nodal lines, and associated surface signatures such as Fermi arcs and drumhead-like states. When spin-orbit coupling is introduced, the magnetic ordering breaks time-reversal symmetry, thereby generating substantial Berry curvature and resulting in a relatively large anomalous Hall conductivity (939 S cm-1). Furthermore, these inorganic electrides exhibit ultralow work functions (2.6-3.9 eV) on rare-earth-terminated surfaces. Under external electric fields, the 3D interstitial electrons migrate to the surface, forming a quasi-2D electron gas. Significantly, such low work functions can effectively activate N2, enhancing catalytic NH3 synthesis. These findings establish an ideal platform to explore 3D inorganic electrides, along with their topological features, anomalous transport phenomena, low work functions, and NH3 synthesis.