We compute within the effective-mass theory and without adjustable parameters the Stark effect for shallow P donors in Si with anisotropic band structure. Valley-orbit coupling is taken into account in a nonperturbative way and scattering effects of the impurity core are included to properly describe low-lying impurity states. The ground-state energy slightly decreases with increasing electric field up to a critical value Ecr∼25 keV∕cm, at which the donor can be ionized by tunneling due to a field-induced mixing of the “1s-like” singlet ground state with a “2p0-like” excited state in zero field. The resulting ground-state wave function at high field extends significantly outside the potential barrier surrounding the impurity. Calculations of the hyperfine splitting and of the A-shell superhyperfine coupling constants as a function of the electric field complete the work.
Computation of the Stark effect in P impurity states in silicon
BALDERESCHI, ALFONSO;
2006-01-01
Abstract
We compute within the effective-mass theory and without adjustable parameters the Stark effect for shallow P donors in Si with anisotropic band structure. Valley-orbit coupling is taken into account in a nonperturbative way and scattering effects of the impurity core are included to properly describe low-lying impurity states. The ground-state energy slightly decreases with increasing electric field up to a critical value Ecr∼25 keV∕cm, at which the donor can be ionized by tunneling due to a field-induced mixing of the “1s-like” singlet ground state with a “2p0-like” excited state in zero field. The resulting ground-state wave function at high field extends significantly outside the potential barrier surrounding the impurity. Calculations of the hyperfine splitting and of the A-shell superhyperfine coupling constants as a function of the electric field complete the work.Pubblicazioni consigliate
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