A new energy model for the calculation of the surface reconstruction of III-V semiconductors:application to the GaAs (110) surface

A new model is presented for the description of the surface reconstruction of III-V semiconductors. The model not only accounts for rehybridization processes occurring at the surface, but also for electrostatic effects, like a formation of a surface dipole layer. Demanding little calculational effort, the model is applicable to reconstruction in an arbitrary number of layers. For the GaAs (110) surface, reconstruction in up to four layers is considered, resulting in a surface layer tilt angle of 27.4 ± 0.3°, in agreement with most previous experimental and theoretical investigations. The calculated energy gain due to surface reconstruction is 1.2 eV per surface cell. The subsurface reconstruction and the surface dipole layer formation make comparable minor, and opposed, contributions of about 0.02 eV. Reconstruction of the third layer yields a larger energy gain than reconstruction of the second layer. No indication is found supporting a recently suggested tilt angle of 7°.