Quantum-Size Effects on the Pattern Formation of Monatomic-Layer-High Metal Islands on Surfaces

The quantum-size effects are shown to play a crucial role in defining the patterns of metal islands formed on surfaces. The energy in elongated needlelike islands oscillates with the width of the needle, clearly demonstrating the existence of preferred needle widths. The energy of the square or rectangular islands varies periodically with the side length, predicting preference for islands with specific sizes.