Interlayer Exchange Interaction Driven Topological Phase Transition in Antiferromagnetic Electride Gd${}_2$O

Abstract

Based on first-principles calculations, we discover a two-dimensional layered antiferromagnetic (AFM) electride Gd${}_2$O, where anionic excess electrons exist in the interstitial spaces between positively charged cationic layers. It is revealed that each cationic layer composed of three-atom-thick Gd$-$O$-$Gd stacks has in-plane ferromagnetic and out-of-plane AFM superexchange interactions between the localized Gd 4$f$ spins through O 2$p$ orbitals. Furthermore, the interlayer superexchange mediated by the hybridized Gd-5$d$ and interstitial-$s$-like states involves intimate couplings between the spin, lattice, and charge degrees of freedom, thereby inducing simultaneous magnetic, structural, and electronic phase transitions. The resulting ground state with the simple hexagonal lattice hosts massless Dirac fermions protected by nonsymmorphic magnetic symmetry, as well as massive Dirac fermions. We thus demonstrate that the anionic excess electrons in Gd${}_2$O play a crucial role in the emergence of magnetic Dirac semimetal states, therefore offering an intriguing interplay between 2D magnetic electrides and topological physics.

References in corpus (5)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Computing topological invariants without inversion symmetry
• Experimental Demonstration of an Electride as a 2D Material
• Superconductivity in Room Temperature Stable electride and high-pressure phases of alkali metals
• Hidden Weyl Fermions in Paramagnetic Electride Y${}_2$C

Cited by in corpus (2)

• Emerging Two-Dimensional Magnetism in Nonmagnetic Electrides Hf2X (X = S, Se, Te)
• Topological Fermi-arc surface state covered by floating electrons on a two-dimensional electride