Using low-energy electron microscopy we explore the fluctuations of step edges on Pt(111) in the temperature range 1190 K < T < 1520 K. Below 1400 K the relaxation times vary with wave vector q as q3, and above 1400 K as q2, while the observed activation energy changes from 1.25 to 2.75 eV. A discussion shows that surface diffusion is responsible for the rates at low temperatures, and that bulk vacancy diffusion becomes dominant above 1400 K. We infer that a similar crossover must occur for steps on most metal surfaces. The step stiffness is determined as 175±20 meV nm-1 at 1500 K.
|Original language||English (US)|
|Number of pages||9|
|Journal||Philosophical Magazine Letters|
|State||Published - Feb 2004|
ASJC Scopus subject areas
- Condensed Matter Physics