LDA DFT simulations of an isolated silicon donor on the (110) surface of GaAs

The convergence of the band gap state of a single silicon dopant on the (110) surface of GaAs was investigated. By simulating different sized super-cells we were able to show that a 3x4 super-cell provides a well converged calculation for modelling an isolated dopant, with the total energy being converged to 1 part in 1000. The local density of the silicon band gap state was then checked against a number of more intensive calculations and was found to be well converged, with an eigenvalue accurate to within 3 meV.