Experimental and Theoretical Study of the Rotation of Si Ad-dimers on the Si(100) Surface

Scanning tunneling microscopy measurements and first principles density functional theory calculations are used to study the rate of the rotational transition of Si ad-dimers on top of the surface dimer rows of Si(100). The rotation rate and the relative population of the two stable orientations of the ad-dimers are measured as a function of the applied electric field to extract the zero-field behavior. The measured relative stability of the two configurations is used to test the accuracy of various functionals for density functional theory calculations.