标题： 直流加热的Si(111)表面台阶束集的预测普适类 显示英文标题

标题： Predicted universality class of step bunching found on DC-heated Si(111) surfaces

摘要： 协同的实验和数值研究了由于部分带电原子在晶面台阶上的向下迁移引起的台阶聚束现象，证实了关于最小聚束距离$l_{\rm min}$与聚束尺寸$N$的尺度依赖性的理论预测：$l_{\rm min} \sim N^{-\gamma}$，其中$\gamma = 2/3$。 所谓的尺寸尺度指数$\gamma$在半导体、金属和介质材料的倾斜表面实验中被观察到。 仔细的理论研究和数值计算预测了另一个$\gamma = 1/2$的值。 然而，这个值尚未在实验中报告。 我们在此报告了相对于$\gamma = 1/2$的 universality class 中的台阶聚束实验观察结果。 这是通过在约1200$^\circ$摄氏度下，使用直接降流加热Si(111)-斜面的升华过程中监测步骤流动来实现的。在实验中，我们还测量了其他与聚束量相关的特征，例如聚束中步骤的平均总数$N$和平均聚束宽度$W$。 然后我们将研究结果与已发表的实验和数值数据进行比较，以在普适类方面得出理论一致的框架。 我们研究的最终好处不仅在于推进基础知识，还在于为斜面纳米模板的自下而上合成提供进一步指导。 显示英文摘要

摘要： Concerted experimental and numerical studies of step bunching on vicinal crystal surfaces resulting from step-down electromigration of partially charged adatoms, confirmed the theoretical prediction of scaling dependence of the minimal bunch distance $l_{\rm min}$ on the bunch size $N$: $l_{\rm min} \sim N^{-\gamma}$, with $\gamma = 2/3$. The value of the so called size-scaling exponent $\gamma$ was observed in experiments on vicinal surfaces of semiconducting, metallic, and dielectric materials. Careful theoretical investigations and numerical calculations predict a second value of $\gamma = 1/2$. However, this value is still not been reported from experiments. And we report here experimental observation of step bunching in the universality class relative to $\gamma = 1/2$. This is achieved by monitoring step flow during sublimation of Si(111)-vicinals heated by a direct step-down current at ~1200$^\circ$C. In the experiment we also measure other characteristic for the bunching quantities, such as the mean total number of steps in the bunch $N$ and the mean bunch width $W$. We then compare our findings with published experimental and numerical data to arrive at a theoretically consistent framework in terms of universality classes. The ultimate benefit of our study is not only to advance fundamental knowledge but also to provide further guidance for bottom-up synthesis of vicinal nanotemplates.