About electrides

Electrides are materials in which electrons can act as anions

In an electride, some valence electrons are spatially separated from atomic sites and occupy cavities, channels or interlayer regions of a crystal. These interstitial states can form an electronic subsystem with its own bandwidth, filling, interactions and response to external conditions.

What makes an electride different

In most ionic solids, anions are atoms or molecular groups. In an electride, part of the electronic charge is localized in a crystallographic void and acts as an anion. The resulting state can be identified through its spatial distribution, symmetry and relation to atomic bands.

An electronic subsystem in the crystal

Interstitial electrons can be localized as quasi-atomic states, form channels, or occupy layers between ionic sheets. Their bandwidth, filling and localization are especially sensitive to pressure, strain, stacking and local distortions.

Dimensionality and magnetic states

Electrenes are ultrathin forms derived from layered electrides. Magnetrides and magnetrenes name cases where an interstitial electronic subsystem develops magnetic order. Here these are related phenomena within electride physics, rather than separate material families.

What theory can establish

First-principles calculations connect structure to electronic states and stability. Localized Wannier functions, screened interactions and many-body methods can test whether an interstitial subsystem is itinerant, localized, magnetic or close to a correlation-driven transition.

About electrides

Short glossary

Interstitial electron: An electron density maximum centered in a crystal void, channel or interlayer region rather than on an atomic nucleus.
Electride state: An electronic state in which interstitial electrons act as anionic charge carriers and can form a distinct subspace near the Fermi level.
Electrene: An ultrathin, low-dimensional material derived from a layered electride.
Wannier function: A localized representation of an electronic subspace. Cavity-centered Wannier functions make it possible to construct models for interstitial states.
DFT+DMFT: A combination of density-functional theory and dynamical mean-field theory used to treat local dynamical electronic correlations.

Scientific claims on this site are drawn from the listed publications and the official RSF project record. Predictions, computed results and experimentally established observations are distinguished in the relevant context.