OBSERVATIONS OF SURFACE TEMPORAL FLUCTUATIONS BY LOW-ENERGY-ELECTRON DIFFRACTION

We present evidence for equilibrium temporal fluctuations in a high re solution low energy electron diffraction (LEED) experiment. These fluc tuations are the reciprocal space analog of current fluctuations in fi eld emission microscopy and therefore can be used to extract surface k inetic information. We show that even when the electron beam illuminat es an area larger than its correlation length, time correlated data ca n be extracted from LEED. To demonstrate this, we present time depende nt data from a W(430) surface, which reflects thermal step fluctuation s. Our results illustrate the potential of LEED as a real time, ultraf ast probe. [S0031-9007(95)07297-4].