Fullband quantization analysis reveals a third valley in [001] silicon inversion layers

This letter presents calculations of the silicon two-dimensional (2-D) band structure obtained by accounting for the fullband energy dispersion of the three-dimensional silicon crystal, as derived from the non-local-pseudopotential method. The most interesting result is the identification of a third valley for the 2-D electron gas in the [001] quantization direction, besides the two families of subbands (the unprimed and primed ones) universally considered according to the effective mass approximation.