Investigation of electronic, elastic, and optical properties of topological electride Ca3Pb via first-principles calculations*

Abstract

Electrides are unique materials with the anionic electrons confined to the interstitial sites, expecting important applications in various areas. In this work, the electronic structure and detailed physical properties of topological electride Ca3Pb are studied theoretically. By comparing the crystal structures and band structures of Ca3Pb and Ca3PbO, we find that after removing O2– ions from Ca3PbO, the remaining electrons are confined in the vacancies of the Ca6 octahedra centers, playing the role as anions and forming an additional energy band compared with that of Ca3Pb. These interstitial electrons partially result in the low work function of Ca3Pb. Moreover, the calculated mechanic properties imply that Ca3Pb has a strong brittleness. In addition, the dielectric functions and optical properties of Ca3Pb are also analyzed.