Observations of surface temporal fluctuations by low energy electron diffraction

We present evidence for equilibrium temporal fluctuations in a high resolution low energy electron diffraction (LEED) experiment. These fluctuations are the reciprocal space analog of current fluctuations in field emission microscopy and therefore can be used to extract surface kinetic information. We show that even when the electron beam illuminates an area larger than its correlation length, time correlated data can be extracted from LEED. To demonstrate this, we present time dependent data from a W(430) surface, which reflects thermal step fluctuations. Our results illustrate the potential of LEED as a real time, ultrafast probe. [S0031-9007(95)07297-4].