论文标题
现场离子显微镜中化学对比度的准确计算
Accurate computation of chemical contrast in field ion microscopy
论文作者
论文摘要
我们提出了一种计算方法，以模拟在场离子显微镜（FIM）中观察到的局部对比度。它基于使用Tersoff-Hamann方法的密度功能理论，如扫描隧道显微镜（STM）所做的那样。一个关键要求是对表面状态波功能尾部的高度准确计算。为了从标准迭代的全球求解器中完善Kohn-Sham状态，我们通过反向集成算法（extra）介绍并讨论尾巴的外推。衰减的尾巴是通过使用Numerov样算法的反向积分（从外部）获得的。然后，迭代地进行了迭代条件，以匹配靠近表面的平面波波波函数的值。我们通过分析和显示Ni表面TA的化学对比度来证明所提出的算法的性能。
We present a computational approach to simulate local contrast observed in Field Ion Microscopy (FIM). It is based on density-functional theory utilizing the Tersoff-Hamann approach as done in Scanning Tunneling Microscopy (STM). A key requirement is the highly accurate computation of the surface states' wave-function tails. To refine the Kohn-Sham states from standard iterative global solvers we introduce and discuss the EXtrapolation of Tails via Reverse integration Algorithm (EXTRA). The decaying tails are obtained by reverse integration (from outside in) using a Numerov-like algorithm. The starting conditions are then iteratively adapted to match the values of plane-wave Kohn-Sham wave functions close to the surface. We demonstrate the performance of the proposed algorithm by analysing and showing the chemical contrast for Ta at Ni surface.
