First-Principles Study of 180⁰ Domain Walls in BaTiO₃: Mixed Bloch-Néel-Ising Character

The 180⁰ ferroelectric domain walls (FDWs) have long been regarded as purely Ising type in ferroelectrics, but recent theoretical works suggested that they can also have Néel- and/or Bloch-like rotations. Using a combination of first-principles calculations with phase-field simulations, we studied the 180⁰ FDWs on different crystallographic planes in prototypical ferroelectric perovskite BaTiO ₃ . The polarization profiles of 180 FDWs on (100) and (410) planes revealed that the (100)- and (410)-FDWs both exhibit Néel-like character besides their intrinsic Ising character, while the (410)-FDW also simultaneously shows a Bloch-like oblique of ~6 nm, as a consequence of the deviation of polarization gradient from the high symmetry direction. Due to the existence of the Néel-like component of polarization, 180⁰ FDWs in BaTiO ₃ exhibit a multilayer charge redistribution and thus may strongly trap charged defects.