DOES HIGH TEMPERATURE IONIC SUPERCONDUCTIVITY EXISTS?

The basic idea is that we try to find some materials in which bosonic ions with sufficiently small effective mass are used as charge carriers instead of Cooper's pairs in order to provide high temperature ionic superconductivity. Ionic crystals LiCl, LiF, LiBr and LiI were considered with lithium isotope Li⁶. Calculations show that Bose condensation temperature for lithium ions in these crystals is of the order of 10^-34–10^-43 K. If, however, the crystal is compressed so that the wave functions of neighboring lithium ions are sufficiently overlapped, then Bose-condensation temperature of Li⁶-ions can be increased significantly. Our estimates show that by compressing the crystals by 20–22% in all three directions, one can raise the Bose-condensation temperature in all crystals considered to above room temperature. To realize materials with room temperature superconductivity in practice, the use of molecular beam epitaxy is proposed for the formation of heterostructures from thin and thick layers of thoughtfully chosen composition.