Intermetallic Ca3Pb: a topological zero-dimensional electride material

Abstract

Based on first-principles calculations, we report the concept of topological electride materials in this paper. It is found that the intermetallic Ca₃Pb compound is a zero-dimensional electride, where the excess electrons are well localized at the 1b (0.5,0.5,0.5) lattice voids. These localized electrons serve as anions in the positively charged crystalline framework. Besides the electride properties, intermetallic Ca₃Pb is also a topological material containing various types of fermionic states. The topological and electride properties of Ca₃Pb are robust upon lattice distortions, which are available for practical applications. The quantum phenomena/effects from the fermionic states (e.g. quantum magnetoresistance and momentum-space Klein tunneling effect in Dirac and Weyl materials) in topological electrides are expected to be more pronounced than in conventional topological materials, because of their loosely bound conducting electrons. The current work opens a new research perspective by combining the nature of topological and electride materials.