Fig. 4.

Illustration of the theoretical model. (A) Hybridization between the d and p orbitals of the itinerant electrons that is induced by the Li ion distortion. (B) Noncentrosymmetric electron density distribution induced by the local electric dipole ${\tau }^z$ associated with the Li ion distortion. (C) (Upper) FE coupling $J_{ij}$ (>0) without itinerant electrons and (Lower) anti-FE coupling $J_{ij}^c$ (<0) mediated by itinerant electrons (black dots) with a small Fermi momentum. See SI Appendix, Section S5 for more details. (D) Schematic of the change in the electron transport along the c axis caused by the FE ordering of the Li ions.