Low-temperature nanodoping of protonated LiNbO$_3$ crystals by univalent ions

In the nanocomposite model developed here, crystals are treated as subordinate aggregate of pro- ton-selected structural elements, their blocks, and proton-containing quantum sublattices with preferred transport effects separating them. The formation of stratified reversible hexagonal structures is accompanied with protonation and formation of a dense network of H-bonds ensuring the nanocomposite properties. Nanodoping with H$^+$ ions occurs during processing of crystals and glasses in melts as well as in aqueous solutions of Ag, Tl, Rb, and Cs salts. The isotope exchange H$^+$ $\leftrightarrow$ D$^+$ and ion exchange H$^+$ $\leftrightarrow$ M$^+$ lead to nanodoping of protonated materials with D$^+$ and M$^+$ ions. This is manifested especially clearly in Li-depleted nonequilibrium LiNbO$_3$ and LiTaO$_3$ crystals. Low-temperature proton-ion nanodoping over superlattices is a basically new approach to analysis of the structure and properties of extremely nonequilibrium materials.