Fig. 3: Restricted lithium dynamics at LLTO surfaces.
From: Probing lithium mobility at a solid electrolyte surface
a, Plot of the barrier for Li migration along the low-energy pathway (inset), resolved for Li atoms at the surface (blue curve) and in the bulk (brown curve). Lower barriers are calculated for bulk diffusion. b, Lithium vDoS energy distribution at the surface and in bulk LLTO. We found a reduction in the population of low-frequency rattling modes (50–100 cm–1) for the surface lithium ion, which resulted in 40% reduction in entropy. The region in the dashed rectangle is enlarged in the bottom panel of g. c–f, Visualization of bulk LLTO vibrational modes at 62 cm–1 (c), 70 cm–1 (d), 89 cm–1 (e) and 132 cm–1 (f). Arrows indicate the general direction of atom displacement at a particular frequency. Li vibrational dynamics are coupled with cage breathing modes (c,f), as well as the optical longitudinal (d) and transverse (e) modes. g, vDoS of the LLTO cage (top) and Li (bottom) vibrations in the low-frequency range. c–f, The various vibrational modes are indicated. Surface cages show suppressed or blueshifted vibrational modes, which compromises Li interfacial dynamics.
