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HL: Fachverband Halbleiterphysik
HL 26: Poster II
HL 26.43: Poster
Mittwoch, 11. März 2026, 09:30–11:30, P1
Comparative ab initio characterization of LiNbO3, Li3NbO4 and LiNb3O8 — •Frederik Schmidt and Arno Schindlmayr — Universität Paderborn, Department Physik, 33095 Paderborn, Germany
Ferroelectric lithium niobate (LiNbO3) is an important material for nonlinear optical technologies. It is part of the Li2O–Nb2O5 system, whose two components can not only form LiNbO3 but also other phases with different Li:Nb ratios, such as Li3NbO4 or LiNb3O8. Both are studied as possible materials for lithium-ion batteries on their own, but they may also occur as unwanted secondary phases during the growth of lithium niobate crystals when pure LiNbO3 is preferred. As a consequence, it is important to detect and identify the different phases. In this work, we employ ab initio methods including density-functional theory, the GW approximation and the Bethe-Salpeter equation in order to characterize the three compounds with identical computational techniques and convergence parameters. In particular, we compare the density of states, electronic band structure and optical absorption spectrum of Li3NbO4 and LiNb3O8 to LiNbO3. Despite qualitative similarities, our results reveal quantitative differences in the electronic and optical properties that should be clearly measurable in experiments. Compared to LiNbO3, the electronic band gap of Li3NbO4 is 1.0 eV larger and that of LiNb3O8 is 0.4 eV smaller. The optical absorption edges also vary correspondingly.
Keywords: LiNbO3; Li3NbO4; LiNb3O8; electronic band structure; absorption spectrum