A New Characteristic Length Scale on Surfaces

该奖项的目的是通过确定新的特征长度尺度的存在、它对加工条件的依赖以及它对表面形貌的影响来调查新的特征长度尺度的概念。结晶纳米棒的直径约为100 nm，许多表面特征具有相似的尺寸。有趣的是，这个维度的起源仍然未知，而纳米棒的制造已经成为一种常规做法。这个项目关注的是这个维度的起源。假设这个维度是由多层约束的表面原子岛的特征。为了验证这一假设，本研究采用了基于密度泛函理论的从头计算、经典分子力学模拟和晶格动力学蒙特卡罗模拟，并以简单金属铜和金为原型材料。如果成功，建立的表面新特征长度尺度的概念将代表着表面科学的新补充。除了给科学界带来好处外，该奖项的成功还将提供一种控制表面粗糙度或一般表面形态的新手段。例如，了解全套表面特征长度标尺将使硬盘驱动器读取头、晶体纳米棒和可持续能源应用催化剂的科学设计成为可能。该奖项还将为本科生和研究生的教育提供机会，包括在这种情况下代表人数不足的少数族裔研究生。

The objective of this award is to investigate the concept of new characteristic length scale by establishing its existence, its dependence on processing conditions, and its effects on surface morphologies. Crystalline nanorods are on the order of 100 nm in diameter, and many surface features have similar dimension. It is interesting to note that the origin of this dimension remains unknown while nanorods fabrication has become a routine practice. This project focuses on the very origin of this dimension. The hypothesis is that this dimension is characteristic of surface atomic islands that are bounded by multiple layers. Aiming to confirm this hypothesis, the proposed research uses density-functional-theory based ab initio calculations, classical molecular mechanics simulations, and lattice kinetic Monte Carlo simulations; and takes simple metals Cu and Au as the prototype materials. If successful, the established concept of new characteristic length scale on surfaces will represent a new addition to surface science. In addition to the benefit to scientific communities, the success of this award will also provide a new means of controlling surface roughness, or surface morphology in general. For example, understanding the complete set of surface characteristic length scales will enable science-based design of reading head of hard disk drives, that of crystalline nanorods, and that of catalysts for sustainable energy applications. The award will also provide an opportunity for the education of undergraduate and graduate students, including an underrepresented minority graduate student in this case.