Ab initio calculation of valley splitting in monolayer \delta-doped   phosphorus in silicon
  The differences in energy between electronic bands due to valley splitting are of paramount importance in interpreting transport spectroscopy experiments on state-of-the-art quantum devices defined by scanning tunneling microscope lithography. We develop a plane-wave density functional theory description of these systems which is size-limited due to computational tractability. We then develop a less resource-intensive alternative via localized basis functions, retaining the physics of the plane-wave description, and extend this model beyond the capability of plane-wave methods to determine the ab initio valley splitting of well-isolated \delta-layers. In obtaining agreement between plane-wave and delocalized methods, we show that the valley splitting has been overestimated in previous ab initio calculations by more than 50%. 
Daniel W. Drumm, Akin Budi, Manolo C. Per, Salvy P. Russo, and Lloyd   C. L. Hollenberg
cond-mat.mtrl-sci quant-ph