First‐Principles Investigation of the Valley Splitting of Si Quantum Slabs

First‐principles calculations based on density functional theory are performed on silicon (Si) quantum slabs to investigate the valley splitting of the lowest sub‐bands at the Γ point in the conduction band. The calculations show that strong strain in the [110] direction of the slab largely enhances the valley splitting, which may be related to the giant valley splitting observed in a device consisting of silicon‐on‐insulator and buried oxide layers. The relation between the valley splitting and the atomic configuration of the slabs is also examined.