First-principles design of halide-reduced electrides: Magnetism and topological phases

We propose a design scheme for potential electrides derived from conventional materials. Starting with rare-earth-based ternary halides, we exclude halogen anions and perform global structure optimization to obtain thermodynamically stable or metastable phases but having an excess of electrons confined inside interstitial cavities. Then, spin-polarized interstitial states are induced by chemical substitution with magnetic lanthanides. To demonstrate the capability of our approach, we test with 11 ternary halides and successfully predict 30 stable and metastable phases of nonmagnetic electrides subject to three different stoichiometric categories, and successively 28 magnetic electrides via chemical substitution with Gd. 56 out of these 58 designed electrides are discovered for the first time. Two electride systems, the monoclinic AC (A = La, Gd) and the orthorhombic A(2)Ge (A = Y, Gd), are thoroughly studied to exemplify the set of predicted crystals. Interestingly, both systems turn out to be topological nodal line electrides in the absence of spin-orbit coupling and manifest spin-polarized interstitial states in the case of A = Gd. Our work establishes a novel computational approach of functional electrides design and highlights the magnetism and topological phases embedded in electrides.

Automated summary

The study proposes a novel design scheme for potential electrides derived from conventional materials, successfully predicting and discovering a variety of stable and metastable nonmagnetic and magnetic electrides, with the majority being discovered for the first time. Through methods such as chemical substitution, it innovatively achieves the design and discovery of electrides.