Structural Domain Walls in Polar Hexagonal Manganites

摘要

We present a microscopic first-principles study of the neutral structuraldomain walls (DWs) in the multiferroic hexagonal manganites, which have beenshown to exhibit cross-couplings between ferroelectricity and struc- turalantiphase. We find that, in contradiction with previously proposed models, theinterlocked antiphase- ferroelectric domain walls have approximately zerowidth, and their energy is lower than that of antiphase-only orferroelectric-only domain walls. Furthermore, we show that theferroelectric-only and antiphase-only DWs are superpositions of interlockedantiphase ferroelectric (AP+FE) DWs and intermediate domains inevitably existthrough the DWs. Our results shed light on the question of why only AP+FE DWsare observed and how the topological defects emerge in polar hexagonalmanganites.