Pseudopotential total-energy calculations show that the π-bonded chain reconstruction of the Si(111)-(2 x 1) surface could be reached from the ideally bonded surface without increasing the total energy by more than 0.03eV/(surface atom). Hence, the chain surface could be formed easily in the cleavage process. The minimum-energy chain geometry was determined, and the corresponding surface-state dispersion was in remarkable agreement with angle-resolved photo-emission experiments.

Reconstruction Mechanism and Surface-State Dispersion for Si(111)-(2 x 1). J.E.Northrup, M.L.Cohen: Physical Review Letters, 1982, 49, 1349-52