Ceramics Laboratory, EPFL Swiss Federal Institute of Technology, Station 12, Lausanne CH-1015, Switzerland.
Nat Commun. 2013;4:1808. doi: 10.1038/ncomms2839.
Hetero interfaces between metal-oxides display pronounced phenomena such as semiconductor-metal transitions, magnetoresistance, the quantum hall effect and superconductivity. Similar effects at compositionally homogeneous interfaces including ferroic domain walls are expected. Unlike hetero interfaces, domain walls can be created, displaced, annihilated and recreated inside a functioning device. Theory predicts the existence of 'strongly' charged domain walls that break polarization continuity, but are stable and conduct steadily through a quasi-two-dimensional electron gas. Here we show this phenomenon experimentally in charged domain walls of the prototypical ferroelectric BaTiO₃. Their steady metallic-type conductivity, 10(9) times that of the parent matrix, evidence the presence of stable degenerate electron gas, thus adding mobility to functional interfaces.
金属氧化物的异质界面表现出明显的现象，如半导体-金属转变、磁电阻、量子霍尔效应和超导性。预计在组成均匀的界面中也会出现类似的效应，包括铁电畴壁。与异质界面不同，畴壁可以在功能器件内部创建、移动、湮灭和重新创建。理论预测存在“强”带电畴壁，这些畴壁打破极化连续性，但在准二维电子气中稳定且稳定地传导。在这里，我们在原型铁电体 BaTiO₃的带电畴壁中实验证明了这一现象。它们稳定的金属型导电性是母体基质的 10(9)倍，证明了稳定简并电子气的存在，从而为功能界面增加了迁移率。
