Fig. 5: Phase stability determined by the displacement of the Li cation.

a Energy variation as a function of the off-center displacement of the Li cation in cubic KLN125 along different directions. b1 A schematic of the Li cation surrounded by the nearest O anions and K cations. Schematics of the Li cation displaced along b2 < 001>, b3 < 011>, and b4 < 111> directions. The displacement vector is referenced based on the displacements with the lowest energy shown in a and amplified 3 times for illustration. Some nearest atoms along the displacement are also displayed in these figures to guide the eye.