A vitrifying structure transition in the Dy/Mo(112) adsorption system

Abstract

Annealing-driven irreversible structural transitions are studied by low energy electron diffraction in submonolayer Dy films adsorbed on the Mo(112) surface. In a wide coverage range θ > 0.07, Dy overlayers deposited at low temperatures (T≈ 100 K) are ordered and keep their structure upon annealing up to 350-600 K. Near θ = 0.68, the overlayers are stable to high- temperature annealing (Ta = 1000 K) as well, whereas the denser films are metastable and transform to more stable ordered structures. An unusual annealing effect is found for θ < 0.58: the initially ordered metastable phases are replaced by phases having no extended order, which are assumed to be two-dimensional glasses.