Moire polar vortex, flat bands, and Lieb lattice in twisted bilayer BaTiO₃.

ABSTRACT: Through first-principles calculations based on density functional theory, we investigate the crystal and electronic structures of twisted bilayer BaTiO₃. Our findings reveal that large stacking fault energy leads to a chiral in-plane vortex pattern that was recently observed in experiments. We also found nonzero out-of-plane local dipole moments, indicating that the strong interlayer interaction might offer a promising strategy to stabilize ferroelectric order in the two-dimensional limit. The vortex pattern in the twisted BaTiO₃ bilayer supports localized electronic states with quasi-flat bands, associated with the interlayer hybridization of oxygen p_z orbitals. We found that the associated bandwidth reaches a minimum at ∼19^∘ twisting, co

SUBMITTER: Lee S 

PROVIDER: S-EPMC11578177 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature