Computer Simulations of Thin Films and Interfaces

该奖项由先进材料和加工计划授予，并得到化学和材料研究部门的支持。几种计算机模拟技术将应用于研究金属薄膜的形成和性质。模拟模拟了原子沉积在实验室中形成非晶和有序薄膜的过程。为了更好地理解薄膜的稳定性和弹性特性，将分别模拟金属体系中的固-液界面和固-固界面。原子相互作用由嵌入原子方法类型的相互作用势来描述，这种相互作用势将从广泛的凝聚相实验中重现数据。系统的微观结构分析将用于表征非晶膜中的短程有序、有序膜中的缺陷、可控参数对膜形态的影响以及界面处结构相关性的衰减。在模拟中产生的微观模型将用于研究两能级系统、振动模式和薄膜的弹性特性。将与实验数据进行比较：(1)非晶铜锆薄膜的两能级体系和振动模式，(2)铂薄膜在低温下的逐层生长。对金属膜生长、表面形态和表面-液体界面的计算机模拟将澄清特定实验的结果，在某些情况下，将提供对不能直接适用于实验的微观事件的见解。

This award is made in the Advanced Materials and Processing Initiative and is supported by both the Chemistry and Materials Research Divisions. Several computer simulation techniques will be applied to study the formation and properties of thin metallic films. The simulations closely mimic the laboratory formation of both amorphous and ordered thin films by atom deposition. Solid-liquid and solid-solid interfaces in metallic systems will be simulated separately to gain a better understanding of stability and elastic properties of thin films. The atomic interactions are described by the Embedded Atom Method-type interaction potentials that will reproduce data from a wide range of condensed phase experiments. A systematic analysis of the microscopic structure will be used to characterize short-range order in amorphous films, defects in ordered films, the effect of controllable parameters on film morphology, and the decay of structural correlations at interfaces. The microscopic models generated in the simulations will be used to study two-level systems, vibrational modes and elastic properties of the films. Comparison will be made with experimental data on (1) two-level systems and vibrational modes in amorphous copper-zirconium films and, (2) layer-by-layer growth of platinum films at low temperature. %%% Computer simulations of metallic film growth, surface morphology and surface-liquid interfaces will clarify the results of specific experiments and in some cases will provide insights into microscopic events not directly amenable to experiment.