A theoretical study was made of the relative formation energies for possible models of the √19 x √19 reconstruction found under Ga-rich growth conditions at the GaAs (¯1¯1¯1) surface. The energetically most favourable model had fourfold-coordinated Ga atoms on the surface, exhibiting metallic bonding character. This structure differs as regards the electron-counting rule from the well accepted models for the (100), (110) and (111) surfaces of GaAs. The results suggest that it was still possible to explain the stability of the metallic (¯1¯1¯1) surface with a rule similar to the electron-counting rule. Structural Models for the √19 x √19 Reconstruction of the GaAs (¯1¯1¯1) Surface and their Relative Stabilities. M.Haugk, J.Elsner, M.Sternberg, T.Frauenheim: Journal of Physics - Condensed Matter, 1998, 10[21], 4523-32