在酸 (001) 表面的表面自我扩散的应变诱导增强
D Gueckelhorn1,2, A Kersch2, A Ruediger1
1Nanophotonics-Nanoelectronics, Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, 1650, Boul. Lionel-Boulet, Varennes J3X 1P7, Québec, Canada.
概括
(Ti) 扩散是酸表面上最慢的过程. 施加应变可以降低扩散障碍,从而使酸材料的新应用成为可能.
科学领域:
- 材料科学 材料科学 材料科学
- 表面科学是一门学科.
- 计算化学的计算化学
背景情况:
- 酸 (SrTiO3) 是电子和催化剂中的一个关键材料.
- 了解表面自我扩散对于薄膜生长和材料特性至关重要.
- 二氧化 (TiO2) 终结 (001) 表面在实验研究中很常见.
研究的目的:
- 为了研究TiO2-终结的基酸 (001) 表面上的自我扩散机制.
- 为了确定表面自我扩散的速度限制步骤.
- 探索等轴向应变对扩散屏障的影响.
主要方法:
- 使用密度函数理论 (DFT) 的数值调查.
- 对单个原子 (Ti,O) 和分子 (O2,TiO2) 的扩散屏障的计算.
- 在不同程度的压力和拉力应变下模拟表面扩散.
主要成果:
- (Ti) 具有最高的扩散屏障 (~2.20 eV),将其确定为速度限制级.
- 氧 (O) 和Ti原子比O2和TiO2具有更高的能量障碍,表明与表面的电子相互作用.
- 均衡双轴应变 (在-6%至2%之间) 显著降低了表面自我扩散的扩散障碍.
- 塑料变形发生在更大的应变值时.
结论:
- 在酸上的表面自我扩散主要由Ti迁移控制.
- 应变工程提供了一种可行的方法来调整表面扩散动力学.
- 降低的扩散障碍为加速表面重建和酸的新型应用提供了新的可能性.
相关概念视频
Acid Strength and Molecular Structure
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
Brønsted-Lowry Acids and Bases
In 1923, the Brønsted–Lowry definition of acids and bases was proposed by Johannes Brønsted and Thomas Lowry. According to this theory, a Brønsted acid is defined as a species that donates a proton in a chemical reaction and gets converted to its conjugate base. A Brønsted base is defined as a species that accepts a proton in a chemical reaction and gets converted into its conjugate acid. These transfers of protons are caused by the displacement of electrons in these reactions, which is...
Molecular Structure and Acidity
An acid can be deprotonated to form a conjugate base or an anion. If the produced anion is more stable, then the acid is stronger. On the contrary, if the anion is unstable, then the acid is weaker. Hence, to determine the acidity of the compound, the stability of its conjugate base is studied using various factors.
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
Acid-Catalyzed Hydration of Alkenes
Alkenes react with water in the presence of an acid to form an alcohol. In the absence of acid, hydration of alkenes does not occur at a significant rate, and the acid is not consumed in the reaction. Therefore, alkene hydration is an acid-catalyzed reaction.
Substituent Effects on Acidity of Carboxylic Acids
The acidity of carboxylic acids is influenced by the nature of the substituents bounded to the functional group. The acid strength is determined by the stability of the carboxylate anion—the conjugate base formed by dissociating the corresponding carboxylic acid.
Leveling Effect
In acid-base chemistry, the leveling effect refers to the limitation imposed by the solvent on the strength of acids and bases in solution. When a base stronger than the solvent's conjugate base is used, it deprotonates the solvent until the base is entirely consumed, making it ineffective against weaker acids. Conversely, an acid stronger than the solvent's conjugate acid protonates the solvent until the acid is depleted, rendering it ineffective against weaker bases. Essentially, the solvent...


