Abstract
The electronic properties of the (110) surface of both pure and Si-doped bulk GaAs are studied using first-principles total-energy calculations within the local-density functional and pseudopotential approximations. The wave functions of the relaxed configurations are used to generate theoretical scanning-tunneling-microscopy (STM) images. For the clean surface, the buckling angle of the surface Ga-As bond is found to be 26° and the theoretically generated STM images are in good agreement with those obtained from experiment. For the Si-doped GaAs(110) surface, the extra electron of the Si substitutional at a Ga site on the surface is found to be well-localized around the Si atom. In addition, dangling-bond states of surface As atoms bordering the Si substitutional are found to be altered due to the distinctively different chemical property of the Si substitutionals. These features should act as a signature for the location of the substitutional surface Si atoms via either voltage-dependent STM imaging or current-voltage (I-V) measurements of various positions on the surface.
- Received 2 December 1992
DOI:https://doi.org/10.1103/PhysRevB.47.10326
©1993 American Physical Society