异质结
正交晶系
材料科学
凝聚态物理
电子
极地的
密度泛函理论
电子结构
莫特绝缘子
氢
表面状态
曲面(拓扑)
化学
结晶学
晶体结构
物理
光电子学
计算化学
量子力学
数学
有机化学
几何学
天文
作者
Karthik Krishnaswamy,Anderson Janotti,Lars Bjaalie,Chris G. Van de Walle
出处
期刊:Journal of vacuum science & technology
[American Institute of Physics]
日期:2021-11-01
卷期号:39 (6)
被引量:1
摘要
Using first-principles techniques based on hybrid density functional calculations, we study the stability, energetics, and electronic structure of the (001) surface of the Mott insulator GdTiO3 (GTO), which has an orthorhombic perovskite structure. Interestingly, we find the bare unreconstructed (but relaxed) polar surface terminated by a TiO2 plane to be very stable with a low surface energy (71 meV/Å2). As a test for stability of the TiO2 termination against reconstructions, we studied the influence of an H adatom. Hydrogen is known to form strong bonds with surface O atoms and passivate surface states, but contrary to expectations, hydrogen does not lead to a lowering of the GTO surface energy. We explain the energetics based on the surface electronic structure. We also address the interaction between the TiO2-terminated GTO surface and the high-density two-dimensional electron gas (2DEG) that can be formed at an SrTiO3 (STO)/GTO heterointerface. Unlike the situation in STO/LaAlO3 (LAO) heterostructures, where the LAO surface acts as a sink for electrons, the GTO surface does not drain electrons away from the 2DEG.
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