Electronic correlations and intrinsic magnetism of interstitial quasi-atomic states in Li8Au electride

Abstract

We investigate the electronic sub-system of a recently designed Li₈Au superconducting electride to reveal its many-body correlated nature and magnetic properties. Using maximally localized Wannier functions (MLWFs) to describe the interstitial anion electron (IAE) states, it was found that these states are partially occupied with a population of 1.5e⁻ and have negligible hybridization with the almost completely filled p-Au states. The averaged interaction screened Hubbard parameter U for quasi-atomic IAE states evaluated by the constrained random-phase approximation (CRPA) method is 2 eV, comparable to the width of the electride band suggesting moderate electronic correlations. Using dynamical mean field theory (DMFT) approach we found that IAEs in Li₈Au electride behave as magnetic centers and possess their own well localised magnetic moments of 0.5μ_B per quasi-atomic IAE. The obtained results deepen the understanding of the significance of many-body effects in the IAE subsystem of electronic states and reveal the mechanism for the formation of intrinsic magnetic moments on IAEs, which behave like ferromagnetic quasi-atoms in the Li₈Au electride. Overall, the observed correlation effects in Li₈Au emphasize their importance in materials with excess electrons confined in cavities.