We report the low-frequency noise behaviors in quasi-two-dimensional (quasi-2D) electron systems based on complex oxide heterostructures. First, the surface 2D electron gas (2DEG) on SrTiO₃ (STO) exhibits the $1/f^{\alpha }$-type current power spectral density (PSD) with $\alpha \sim 1.39$. The non-unity exponent $\alpha$ indicates the discrepancy between the depth distributions of electrons and oxygen vacancies in the STO substrate. Second, the amorphous LaAlO₃/KTaO₃ (LAO/KTO) interface, another quasi-2D electron system, shows Lorentzian components of PSD at a high-frequency region around 1 kHz, implying that the amorphous overlayer can provide additional shallow charge-trapping sites to the quasi-2D electrons in the crystalline KTO substrate. Lastly, ultrathin SrRuO₃ (SRO) film grown on STO substrate exhibits the Lorentzian components of PSD at a low-frequency region around 200 Hz. The slight suppression of the fast charge trapping is attributed to the intrinsic band bending at the interface between film and substrate. These results will provide a guideline for understanding the defect-induced charge trapping and the relevant electron dynamics in the quasi-2D electron systems as well as the oxide-based electronic materials in general.

我们报告了基于复杂氧化物异质结构的准二维（准2D）电子系统中的低频噪声行为。_{首先，SrTiO 3} (STO)上的表面二维电子气 (2DEG)表现出$1/F^{\alpha }$型电流功率谱密度 (PSD)$\alpha ～1.39$。非统一指数$\alpha$表示 STO 衬底中电子和氧空位的深度分布之间的差异。其次，非晶 LaAlO ₃ /KTaO ₃ (LAO/KTO) 界面（另一种准二维电子系统）在 1 kHz 左右的高频区域显示出 PSD 的洛伦兹分量，这意味着非晶覆盖层可以提供额外的浅电荷捕获晶体 KTO 衬底中准二维电子的位点。最后，在 STO 衬底上生长的超薄 SrRuO ₃ (SRO) 薄膜在 200 Hz 左右的低频区域表现出 PSD 的洛伦兹分量。快速电荷捕获的轻微抑制归因于薄膜和基底之间界面处的本征能带弯曲。这些结果将为理解准二维电子系统以及一般氧化物电子材料中缺陷引起的电荷捕获和相关电子动力学提供指导。