Departments of Physics and Mathematics, Colorado State University, Fort Collins, Colorado 80523, USA.
Division of Science and Engineering, Pennsylvania State University, Abington, Abington, Pennsylvania, 19001, USA.
Phys Rev E. 2023 Jan;107(1-1):014801. doi: 10.1103/PhysRevE.107.014801.
We study the nanoscale patterns that form on the surface of a rotating sample of an elemental material that is bombarded with a broad noble gas ion beam for angles of incidence θ just above the critical angle for pattern formation θ_{c}. The pattern formation depends crucially on the ion energy E. In simulations carried out in the low-energy regime in which sputtering is negligible, we find disordered arrays of nanoscale mounds (nanodots) that coarsen in time. Disordered arrays of nanodots also form in the high-energy regime in which there is substantial sputtering, but no coarsening occurs close to the threshold angle. Finally, for values of E just above the sputter yield threshold, nanodot arrays with an extraordinary degree of hexagonal order emerge for a range of parameter values, even though there is a broad band of linearly unstable wavelengths. This finding might prove to be useful in applications in which highly ordered nanoscale patterns are needed.
我们研究了在元素材料旋转样品表面上形成的纳米级图案，该样品受到宽束贵金属离子束的轰击，入射角θ略高于图案形成的临界角θ_{c}。图案形成与离子能量 E 密切相关。在模拟中，我们发现在溅射可以忽略的低能区中，存在无序排列的纳米级土丘（纳米点）阵列，这些纳米点会随着时间的推移而粗化。在高能区中也会形成无序的纳米点阵列，其中存在大量的溅射，但在接近阈值角的情况下不会发生粗化。最后，对于稍高于溅射产额阈值的 E 值，即使存在宽带线性不稳定波长，在一系列参数值下也会出现具有极高六边形有序度的纳米点阵列。这一发现可能在需要高度有序纳米级图案的应用中证明是有用的。
