论文标题
Srtio $ _3 $/LAALO $ _3 $的极性场驱动电导率：一项混合功能研究
Polarity-field driven conductivity in SrTiO$_3$/LaAlO$_3$: a hybrid functional study
论文作者
论文摘要
二维电子系统（2DE）的起源出现在带绝缘子的（001）界面$ \ rm srtio_3 $和$ \ rm laalo_3 $的起源已在极性灾难的框架内合理化了。这意味着存在极性$ \ rm laalo_3 $覆盖剂（$ 4〜 \ rm U.C. $）的2DES出现：厚度$ \ rm laalo_3 $覆盖物的极性灾难是通过供应者的出现或供应者的稳定性来避免使用$ \ rm rm rm rm rm rm rm rm rm rm rM基材。在实验中观察到临界厚度的观察，支持这些假设。然而，关于这些可能的机制实际上是首先发生的哪种机制仍有公开辩论。使用杂交功能密度功能理论，我们在相同近似水平的水平上重新检查了这些机制。特别是，我们阐明了供体缺陷在这些异质结构中的作用，并认为在通常的生长条件下，电场驱动的氧气空位稳定和老挝表面的氢吸附在老挝的厚度上，其厚度比Zener崩溃所需的较小。
The origin of the 2-dimensional electron system (2DES) appearing at the (001) interface of band insulators $\rm SrTiO_3$ and $\rm LaAlO_3$ has been rationalized in the framework of a polar catastrophe scenario. This implies the existence of a critical thickness of polar $\rm LaAlO_3$ overlayer ($4~\rm u.c.$) for the appearance of the 2DES: polar catastrophe for thick $\rm LaAlO_3$ overlayer is avoided either through a Zener breakdown or a stabilization of donor defects at the $\rm LaAlO_3$ surface, both providing electrons to dope the substrate. The observation of a critical thickness is observed in experiments, supporting these hypotheses. Yet, there remains an open debate about which of these possible mechanisms actually occurs first. Using hybrid functional Density Functional Theory, we re-examine these mechanisms at the same level of approximation. Particularly, we clarify the role of donor defects in these heterostructures, and argue that, under usual growth conditions, electric-field driven stabilization of oxygen vacancies and hydrogen adsorbates at the LAO surface occur at a smaller LAO thickness than required for Zener breakdown.
