Adsorption of benzene on Si(100)-(2x1): Adsorption energies and STM image analysis by ab initio methods - art. no. 085314

We model the adsorption and STM imaging of benzene on Si(100) by using firs t principles density functional methods and a perturbation approach for the tunneling current. The simulations are well in accordance with experimenta l data and reproduce the adsorption energies and the energy differences bet ween adsorption sites remarkably well. We were able to simulate images and line scans of the two principal adsorption geometries and to show that they reproduce the actual measurements. The chemical nature of the tip in measu rements is discussed and it is shown that a tip structure protruding severa l layers from the crystal face and terminated by a tungsten atom gives the best agreement with measurements. The results confirm the view that tunneli ng is dominated by a single tip atom.