Mokkath Junais Habeeb, Muhammed Mufasila Mumthaz, Chamkha Ali J
Quantum Nanophotonics Simulations Lab, Department of Physics, Kuwait College of Science and Technology, Doha Area, 7th Ring Road, Kuwait City P.O. Box 27235, Kuwait.
School of Engineering & Computing, American International University, Saad Al Abdullah-East of Naseem, Block 3, Kuwait.
Nanomaterials (Basel). 2021 Dec 28;12(1):76. doi: 10.3390/nano12010076.
Metadynamics is a popular enhanced sampling method based on the recurrent application of a history-dependent adaptive bias potential that is a function of a selected number of appropriately chosen collective variables. In this work, using metadynamics simulations, we performed a computational study for the diffusion of vacancies on three different Al surfaces [reconstructed Al(100), Al(110), and Al(111) surfaces]. We explored the free energy landscape of diffusion and estimated the barriers associated with this process on each surface. It is found that the surfaces are unique regarding vacancy diffusion. More specically, the reconstructed Al(110) surface presents four metastable states on the free energy surface having sizable and connected passage-ways with an energy barrier of height 0.55 eV. On the other hand, the reconstructed Al(100)/Al(111) surfaces exhibit two/three metastable states, respectively, with an energy barrier of height 0.33 eV. The findings in this study can help to understand surface vacancy diffusion in technologically relevant Al surfaces.
元动力学是一种流行的增强采样方法，它基于对历史依赖的自适应偏差势的反复应用，该偏差势是所选数量的适当选择的集体变量的函数。在这项工作中，我们使用元动力学模拟对空位在三种不同的铝表面（重构的Al(100)、Al(110)和Al(111)表面）上的扩散进行了计算研究。我们探索了扩散的自由能景观，并估计了每个表面上与该过程相关的势垒。发现这些表面在空位扩散方面具有独特性。更具体地说，重构的Al(110)表面在自由能表面上呈现四个亚稳态，具有大小适中且相连的通道，能量势垒高度为0.55电子伏特。另一方面，重构的Al(100)/Al(111)表面分别呈现两个/三个亚稳态，能量势垒高度为0.33电子伏特。本研究中的发现有助于理解技术上相关的铝表面中的表面空位扩散。
