Observation of Finite-Size Effects on a Structural Phase Transition of 2D Nanoislands

Abstract

We study a reversible, temperature-driven structural surface phase transition of Pb/Si(111) nanoislands with a variable-temperature scanning tunneling microscope. Our quantitative measurements indicate that the transition temperature decreases with decreasing island and domain size. The boundaries of the nanoislands also influence the transition. Careful examination of the change in the interior structure of nanoislands near the transition temperature allows us to image the effects of the thermal fluctuations.