Department of Materials, Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland.
Nat Commun. 2013;4:1540. doi: 10.1038/ncomms2545.
The domain structure in the multiferroic hexagonal manganites, h-RMnO(3) (R=Sc, Y, Dy-Lu), is currently intensely investigated, motivated by the observation of nanoscale electrical conductivity at the domain walls and intriguing sixfold topological defects at their meeting points, as well as reports of coupling between ferroelectricity, magnetism and structural antiphase domains. The detailed structure of the domain walls, as well as the origin of such couplings, however, was previously unknown. Here we use first-principles electronic structure calculations to elucidate the structure and properties of the structural domain walls in the hexagonal manganites. Our results allow us to explain why ferroelectric domain walls are always simultaneously antiphase walls, propose a mechanism for ferroelectric switching through domain-wall motion, suggest a structure for the observed sixfold topological defects and predict a topological protection of experimentally observed stripe domains in hexagonal manganites.
多铁性六方锰氧化物 h-RMnO(3)（R=Sc、Y、Dy-Lu）的畴结构目前受到了广泛关注，这是因为在畴壁处观察到了纳米尺度的导电性，以及在其交汇点处出现了有趣的六重拓扑缺陷，还有报道称铁电性、磁性和结构反铁相畴之间存在耦合。然而，畴壁的详细结构以及这种耦合的起源此前尚不清楚。在这里，我们使用第一性原理电子结构计算来阐明六方锰氧化物中结构畴壁的结构和性质。我们的结果解释了为什么铁电畴壁总是同时也是反铁相畴壁，提出了通过畴壁运动实现铁电开关的机制，为观察到的六重拓扑缺陷提出了一种结构，并预测了在六方锰氧化物中实验观察到的条纹畴的拓扑保护。
