Huge susceptibility increase within the (1−x) TeO2 + x TeO3 crystal system: Ab initio calculation study

Highlights: • Minor role of the electron lone pairs of Te atom on non-linear optic properties. • TeIVO4 → TeVIO6 evolution induces an augmentation of the χ3 susceptibility. • The Te-O-Te chain -length influences on the lattice χ3 susceptibility. -- Abstract: The ab initio calculations performed for the TeO2 → Te4O9 → Te2O5 → TeO3 series of crystal lattices have revealed that, in this series, the average χ3 non-linear susceptibility increases for about 10 times. Such a huge effect is attributed to the strong augmentation of the Te atom d-function contributions in valence molecular orbitals, which accompanies the Te4+ → Te6+ transformation. The results obtained allow concluding that the TeO3-related materials can be of interest in non-linear optic device engineering