Department of Physics, Beijing Normal University, Beijing, 100875, China.
National Institute of Materials Physics, Atomistilor 405A, Magurele, Ilfov, 077125, Romania.
Sci Rep. 2018 Jan 9;8(1):195. doi: 10.1038/s41598-017-18583-5.
We explored in-gap states (IGSs) in perovskite oxide heterojunction films. We report that IGSs in these films play a crucial role in determining the formation and properties of interfacial two-dimensional electron gas (2DEG). We report that electron trapping by IGSs opposes charge transfer from the film to the interface. The IGS in films yielded insulating interfaces with polar discontinuity and explained low interface carrier density of conducting interfaces. An ion trapping model was proposed to explain the physics of the IGSs and some experimental findings, such as the unexpected formation of 2DEG at the initially insulating LaCrO/SrTiO interface and the influence of substitution layers on 2DEG.
我们研究了钙钛矿氧化物异质结薄膜中的带隙态（IGS）。我们报告称，这些薄膜中的 IGS 在确定界面二维电子气（2DEG）的形成和性质方面起着至关重要的作用。我们报告称，IGS 通过电子俘获来反对电荷从薄膜转移到界面。薄膜中的 IGS 产生了具有极性不连续性的绝缘界面，并解释了具有低界面载流子密度的导电界面。提出了一个离子俘获模型来解释 IGS 的物理性质和一些实验发现，例如最初绝缘的 LaCrO/SrTiO 界面上意外形成 2DEG 以及替代层对 2DEG 的影响。
