Formation of Quasi-One-Dimensional [Formula presented] Structures by in situ Oxidation of Cu(100)

Epitaxial [Formula presented] islands on a Cu(100) surface formed through oxidizing Cu(100) films at 600°C in an ultrahigh vacuum transmission electron microscope were observed to undergo a shape transition from initially square shaped islands to elongated islands at a critical size of [Formula presented]. Our experimental data on the elongation of [Formula presented] islands agree with the energetic calculations based on the balance between surface and interface energies and the elastic stress relaxation in the three-dimensional islands. We developed a kinetic model based on oxygen surface diffusion that fits well with the observed volume evolution of the [Formula presented] islands.