ICQD/Hefei National Laboratory for Physical Sciences at Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nanoscale. 2017 Aug 17;9(32):11553-11565. doi: 10.1039/c7nr02458d.
Defects on oxide surfaces play a crucial role in surface reactivity and thus it is crucial to understand their atomic and electronic structures. The defects on anatase TiO(001)-(1 × 4) surfaces are found to be highly reactive; however, due to the surface reconstruction, the defects exhibit a complicated character in different experiments that make it very challenging to determine their atomic structures. Here we present a systematic first-principles investigation of the defects on anatase TiO(001)-(1 × 4) surfaces based on a global-search adaptive genetic algorithm (AGA) and density functional theory (DFT). For different Ti-O ratios, we identify the low energy defect structures, investigate their electronic structure using a hybrid functional, and map their regions of stability under realistic conditions. We successfully find novel oxygen vacancy (O) and Ti interstitial (Ti) structures that are different from the conventional ones in terms of their charge localization, magnetic state, and their scanning-tunneling-microscopy bright-dark image signature. This provides an insight into the complex geometric and electronic structure of the surface defects, and resolves several experimental discrepancies.
氧化物表面的缺陷在表面反应性中起着至关重要的作用，因此了解其原子和电子结构至关重要。研究发现，锐钛矿 TiO(001)-(1 × 4)表面的缺陷具有很高的反应活性；然而，由于表面重构，不同实验中缺陷表现出复杂的特征，这使得确定其原子结构极具挑战性。在这里，我们基于全局搜索自适应遗传算法（AGA）和密度泛函理论（DFT），对锐钛矿 TiO(001)-(1 × 4)表面的缺陷进行了系统的第一性原理研究。对于不同的 Ti-O 比，我们确定了低能量缺陷结构，使用杂化泛函研究了它们的电子结构，并绘制了它们在实际条件下的稳定区域图。我们成功地找到了新颖的氧空位 (O) 和 Ti 间隙 (Ti) 结构，它们在电荷定位、磁态和扫描隧道显微镜亮暗图像特征方面与传统结构不同。这为表面缺陷的复杂几何和电子结构提供了深入了解，并解决了几个实验上的差异。
