Scanning-tunneling-microscopy images: A fullyab initioapproach

Abstract

A fully {ital ab initio} approach to scanning-tunneling-microscope (STM) images is presented, treating the sample {ital and} the tip as {ital a single system}. The approach combines density functional theory with the Kubo-Greenwood formalism for the conductivity. The STM images are calculated by taking into account atomic relaxations that occur on {ital both} the surface and the tip due to their mutual interactions. Illustrative examples will be presented for the case of a clean Al(110) surface and the same surface with a vacancy, showing that buckling relaxations occur that {ital smooth} the STM images, reducing the observable corrugation of the surface. {copyright} {ital 1999} {ital The American Physical Society}