论文标题
铁电薄膜中电子掺杂的域结构的演变
Evolution of domain structure with electron doping in ferroelectric thin films
论文作者
论文摘要
To minimize their electrostatic energy, insulating ferroelectric films tend to break up into nanoscale ``Kittel'' domains of opposite polarization that are separated by uncharged 180$^\circ$ domain walls.在这里，我报道了耦合的Landau-Ginzburg-Devonshire和Schrödinger方程的自一稳态解决方案，用于电子掺杂的铁电薄膜。该模型基于Laalo $ _3 $/srtio $ _3 $接口，其中Srtio $ _3 $底物是通过阳离子替代或应变制成铁电的。我发现电子兴奋剂破坏了基特尔域。随着二维电子密度$ n_ \ mathrm {2d} $增加，锯齿形域墙配置的跨界平稳。域壁具有正电荷，但由电子气体补偿，电子气体将自身固定在域壁上，屏幕去极化场。域墙以完美筛选的极限接近平坦的头对头配置。偏振轮廓可以通过外部偏置电压来操纵，并且可以在铁电膜的表面之间切换电子气体。
To minimize their electrostatic energy, insulating ferroelectric films tend to break up into nanoscale ``Kittel'' domains of opposite polarization that are separated by uncharged 180$^\circ$ domain walls. Here, I report on self-consistent solutions of coupled Landau-Ginzburg-Devonshire and Schrödinger equations for an electron-doped ferroelectric thin film. The model is based on LaAlO$_3$/SrTiO$_3$ interfaces in which the SrTiO$_3$ substrate is made ferroelectric by cation substitution or strain. I find that electron doping destabilizes the Kittel domains. As the two-dimensional electron density $n_\mathrm{2D}$ increases, there is a smooth crossover to a zigzag domain wall configuration. The domain wall is positively charged, but is compensated by the electron gas, which attaches itself to the domain wall and screens depolarizing fields. The domain wall approaches a flat head-to-head configuration in the limit of perfect screening. The polarization profile may be manipulated by an external bias voltage and the electron gas may be switched between surfaces of the ferroelectric film.
