Total-energy calculations for the 2 × 1 antiferromagnetic and 1 × 1 paramagnetic states of the Si(111)-(1 × 1) surface

Abstract
The energies of the 2 × 1 antiferromagnetic and 1 × 1 paramagnetic states of the Si(111)-(1 × 1) surface are calculated as a function of relaxation using the pseudopotential method within the local-spin-density approximation. The energy difference between these two states depends strongly on the relaxation and on the form of the local exchange-correlation-energy functional. We also find that the paramagnetic state of the π-bonded chain geometry is stable against antiferromagnetic spin ordering.