Prediction of Stoner-Type Magnetism in Low-Dimensional Electrides

Electrides are special ionic solids with excess cavity-trapped electrons serving as anions. Despite the extensive studies on electrides, the interplay between electrides and magnetism is not well understood due to the lack of stable magnetic electrides, particularly, the lack of inorganic magnetic electrides. Here, on the basis of the mechanism of Stoner-type magnetic instability, we propose that in certain electrides the low-dimensionality can facilitate the formation of a magnetic ground state because of the enhanced density of states near the Fermi level. To be specific, A ₅ B ₃ (A = Ca, Sr, Ba; B = As, Sb, Bi) (one-dimensional, 1D), Sr ₁₁ Mg ₂ Si ₁₀ (zero-dimensional, 0D), Ba ₇ Al ₁₀ (0D), and Ba ₄ Al ₅ (0D) have been identified as stable magnetic electrides with spin-polarization energies of tens to hundreds of millielectronvolts per formula unit. Especially for Ba ₅ As ₃ , the spin-polarization energy can reach up to 220 meV. Furthermore, we demonstrate that the magnetic moment and spin density mainly derive from the interstitial anionic electrons near the Fermi level. Our work paves a way for the search of stable magnetic electrides and further exploration of the magnetic properties and related applications in electrides.