Nanostructures at surfaces from substrate-mediated interactions

Recent theoretical and experimental studies indicate that adsorbate-adsorbate interactions mediated by a solid surface can be significant enough to influence the formation of nanostructures during thin-film epitaxy. Here, we show that these electronic interactions lead to the formation of repulsive barriers surrounding small adsorbate islands at surfaces. The dependence of these barriers on island size and shape actuates sharp island-size distributions, which can be manipulated by changing growth conditions to yield selected island sizes and shapes. The existence of these interactions opens new prospects for engineering nanostructures at surfaces.