Dynamic behavior and phase transition of magic Al clusters on Si(111)-7x7 surfaces

By means of high-temperature scanning tunneling microscopy, the authors present a direct observation on the dynamic behavior and phase transition of magic Al clusters on Si(111)-7x7 surfaces at high temperature. When the temperature is above 500 degrees C, fast diffusion of magic Al clusters on Si(111)-7x7 surfaces occurs while the magic cluster phase transforms into root 3x root 3-Al phase on downterraces (the downstep side of a terrace). From an Arrhenius plot, the activation energy of magic Al clusters on Si(111)-7x7 surfaces was extracted to be 2.0 +/- 0.3 eV. This study supplies important information for understanding the formation and phase transition process of magic Al nanoclusters on Si(111)-7x7 surfaces. (c) 2006 American Institute of Physics.