Ab initio calculation of valley splitting in monolayer δ-doped phosphorus in silicon
1 School of Physics, The University of Melbourne, Parkville, Victoria 3010, Australia
2 School of Applied Sciences, RMIT University, Melbourne, Victoria 3001, Australia
3 Virtual Nanoscience Laboratory, CSIRO Materials Science and Engineering, Parkville, Victoria 3052, Australia
Nanoscale Research Letters 2013, 8:111 doi:10.1186/1556-276X-8-111Published: 27 February 2013
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 tunnelling microscope lithography. Using VASP, we develop a plane-wave density functional theory description of systems which is size limited due to computational tractability. Nonetheless, we provide valuable data for the benchmarking of empirical modelling techniques more capable of extending this discussion to confined disordered systems or actual devices. We then develop a less resource-intensive alternative via localised basis functions in SIESTA, 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 δ-layers. In obtaining an agreement between plane-wave and localised methods, we show that valley splitting has been overestimated in previous ab initio calculations by more than 50%.