A multiscale view in functional materials

Functional materials show various highly demanded performances originating from intrinsic features related to degrees of freedom in a lattice framework. Presently, deep physical or chemical insights of quantum materials stimulate researchers to clarify multiscale processes within both materials and devices, which may be understood as functional materials that possess energy origin beyond electron contribution. It is of great significance for the design of functional materials to understand the sources of properties of functional materials from the perspective of multi degrees of freedom via multiscale research methods. This short review illustrates the importance and explores the energy source of functional materials from multiple degrees of freedom perspectives. Moreover, we analyzed the multiple degrees of freedom within lithium niobate single crystals to clarify their multiscale features. This short review may, in some cases, provide a perspective for enhancing research scopes of functional materials and recommending some methodologies from multiple degrees of freedom perspectives. A multiscale view at lithium niobate, ranging from Li+, Nb5+ and O2− ions and their chemical bonding features, domain engineering, as well as the regulated frame with LiO6 and NbO6 octahedral stacking. Crystallographic structure clarifies lattice freedom order parameter, demonstrating domain kinetics and phase transition from ferro-to nonferro-state, Jahn-Teller effect, valence electron orbital hybridization, defects causing the local symmetry broken, etc. [Display omitted] •Functional materials research follows their multiscale origin and the perspective of multiple degrees of freedom.•We analyzed the degrees of freedom and coupling effects within the crystallographic structure of lithium niobate.•Studying the quantum effects of lithium niobate is to clarify the quantum source of the macro function of lithium niobate.