Abstract Two-dimensional electron gases (2DEGs) on the SrTiO3 (STO) surface or in STO-based heterostructures have exhibited many intriguing phenomena, which are strongly dependent on the 2DEG-carrier density. We report that the tunability of the 2DEG-carrier density is significantly enhanced by adding a monolayer LaTiO3 (LTO) onto the STO. Ultraviolet (UV) irradiation induced maximum carrier density of the 2DEG in LTO/STO is increased by a factor of ~4 times, compared to that of the bare STO. By oxygen gas exposure, it becomes 10 times smaller than that of the bare STO. This enhanced tunability is attributed to the drastic surface property change of a polar LTO layer by UV irradiation and O2 exposure. This indicates that the 2DEG controllability in LTO/STO is more reliable than that on the bare STO driven by defects, such an oxygen vacancy.

中文翻译：

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通过异质结构增强二维电子气在 SrTiO3 上的可调性

摘要 SrTiO3 (STO) 表面或基于 STO 的异质结构中的二维电子气 (2DEGs) 表现出许多有趣的现象，这些现象强烈依赖于 2DEG 载流子密度。我们报告说，通过在 STO 上添加单层 LaTiO3 (LTO) 显着增强了 2DEG 载流子密度的可调性。与裸 STO 相比，紫外 (UV) 辐射诱导的 LTO/STO 中 2DEG 的最大载流子密度增加了约 4 倍。通过氧气暴露，它变得比裸 STO 小 10 倍。这种增强的可调性归因于极性 LTO 层在紫外线照射和 O2 暴露下的剧烈表面特性变化。这表明 LTO/STO 中的 2DEG 可控性比由缺陷（如氧空位）驱动的裸 STO 更可靠。