The D values obtained from G(t) integration converged to zero when ω = 10 ps, as shown in Fig. . The extent of dynamical changes in PS 4 3from the bulk β-Li 3 PS 4 to the crystalline region in the interfacial model was estimated using the mean q 3 (q 3 ) of PS 4 3units in the crystalline region. Fig. shows the correlation plot between q 3 and D crystal for models with various interface planes. There was a strong negative correlation, with a Pearson correlation coefficient of -0.92, as indicated by the solid line. Models with lower q 3 values resembled the glassy state in terms of PS 4 3rotational motion. The enhancement of Li + diffusion through the rotational motion of PS 4 3units, combined with Li + vibration, is known as the paddle-wheel mechanism in 75Li 2 S-25P 2 S 5 glass. This mechanism may contribute significantly to Li + diffusion. In contrast, the model with the (001) interface, which had the highest q 3 , showed relatively restricted PS 4 3rotational motion, resulting in lower Li + diffusivity. These results highlight the role of interfaces in influencing Li + dynamics.