Inelastic scattering and first principles study of tritium breeder materials Li2TiO3 and Li2ZrO3

Abstract

First ever Compton spectroscopy of Li2TiO3 (LTO) and Li2ZrO3 (LZO) have been performed using 100 mCi 241Am Compton spectrometer. The experimental electron momentum densities (EMDs) of these compounds are compared with the theoretical EMDs computed using various generalized gradient approximations (GGA) under linear combination of atomic orbitals (LCAO) method namely Becke-Lee-Yang-Parr (BLYP), Perdew-Burke-Ernzerhof (PBE), revised Perdew-Burke-Ernzerhof for solids (PBEsol) and Perdew-Wang GGA (PWGGA). The BLYP based theoretical Compton profiles show best agreement with the experimental data for both the Li-ceramics. The electronic structure calculations predicted indirect band gap nature of both compounds with major contributions of Ti-3d, Zr-4d and O-2p states with some minor part due to Li-2sp states around Fermi energy. Further, experimental EVED profiles anticipated more covalent or less ionic character of LTO as compared to LZO. The elastic properties calculations verified mechanical stability of both compounds at ambient temperature and pressure. In addition, the optical properties of LTO and LZO are derived using full potential linearized augmented plane wave (FP-LAPW) method, which revealed high absorbent feature and photoconductive behavior of both compounds in UV region. Moreover, large values of electrical and thermal conductivities at high temperature make them suitable candidates for electrode materials in Li-ion batteries.