Exploring interstitial electronic states in electride materials: DFT+U+V insights into Li8Au

Abstract

Using Li${}_8$Au electride as a model system, we investigate the way to account for local and non-local correlation effects on interstitial states in electrides employing DFT+U+V approach, which incorporates both on-site and inter-site Coulomb interactions. It accurately captures the correlations in the states of the atoms composing the cavity frameworks, which effectively form the electride orbitals localized within these cavities. A comparison between DFT+U+V and Dynamical Mean Field Theory (DMFT), where the interstitial quasi-atomic state is explicitly treated as a correlated impurity, finds that the former is able to reveal the essential features of the Li${}_8$Au electride electronic structure. In this way, it is possible to observe the formation of well-localized magnetic moments that do not belong to the atoms of the crystal lattice framework. These findings provide an effective methodology for identifying the electronic structure of low-dimensional correlated electrides and investigating their related physical properties.