Density-functional calculation of subband structure on semiconductor surfaces

The Hohenberg-Kohn-Sham theory of an inhomogeneous electron gas is applied to the calculation of subband structures of n-channel accumulation and inversion layers on a Si(100) surface. The exchange-correlation effect is shown to be very important and lower the subband energies considerably. In case of accumulation layers it changes the subband structure. The first excited subband becomes really a bound state in contrast to a result of the Hartree approximation. The agreement between the theory and experimental results of intersubband optical transitions is satisfactory. The effective mass and the g factor are also calculated.