Localised Magnetism in 2D Electrides
arXiv:1912.03885 · doi:10.1039/D0TC01223H
Abstract
In this work, we investigate intrinsic magnetic properties of monolayer electrides LaBr and LaBr, where excess electrons do not reside at any atomic orbital and act as anions located at interstitial regions. Having demonstrated that conventional first-principles approaches are incapable of treating such non-atomic magnetic orbitals largely underestimating insulating band gaps, we construct effective electronic models in the basis of Wannier functions associated with the anionic states to unveil the microscopic mechanism underlying magnetism in these systems. Being confined at zero-dimensional cavities in the crystal structure, the anionic electrons will be shown to reveal an exotic duality of strong localisation like in - and -electron systems and large spatial extension inherent to delocalised atomic orbitals. While the former tends to stabilise a Mott-insulating state with localised magnetic moments, the latter results in direct exchange between neighbouring anionic electrons that dominates over antiferromagnetic superexchange interactions. On the basis of the derived spin models, we argue that any long-range magnetic order is prohibited in LaBr by Mermin-Wagner theorem, while intersite anisotropy stabilises weakly coupled ferromagnetic chains along the monoclinic axis in LaBr. Our study shows that electride materials combining peculiar features of both localised and delocalised atomic states constitute a unique class of strongly correlated materials.
References in corpus (14)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
- Maximally localized Wannier functions: Theory and applications
- Gate-tunable Room-temperature Ferromagnetism in Two-dimensional FeGeTe
- The Valley Hall Effect in MoS2 Transistors
- Frequency-dependent local interactions and low-energy effective models from electronic structure calculations
- Atomically Thin CrCl3: An in-Plane Layered Antiferromagnetic Insulator
- Experimental Demonstration of an Electride as a 2D Material
- Anisotropic Spin Hamiltonians due to Spin-Orbit and Coulomb Exchange Interactions
- High-Throughput Identification of Electrides from all Known Inorganic Materials
- Electronic, Dielectric, and Plasmonic Properties of Two-Dimensional Electride Materials XN (X=Ca, Sr): A First-Principles Study
- Role of direct exchange and Dzyaloshinskii-Moriya interactions in magnetic properties of graphene derivatives: CF and CH
- Microscopic theory of electric polarization induced by skyrmionic order in GaVS
- Electronic correlation in the quasi-two-dimensional electride YC