Electron Correlation Effects on Light Emission from Silicon (001) by Scanning Tunneling Microscope

We investigate the electron correlation effects on light emission from dimers on Si(001) induced by scanning tunneling microscope (STM), with the aid of the Hubbard model. In the model, electron transfer between the STM tip and a dimer in the vicinity of the tip accounts for light emission. We demonstrate by the Green function method that the light emission intensity reflects the electronic density of states. As a result, it is suggested that the fundamental parameters related to the electron system, i.e. the electron hopping integral between dimers and Coulomb interactions between electrons in a dimer with opposite spins, can be estimated from the light intensity.