Inter-valley interactions in Si quantum dots

In this paper, we studied the inter-valley interactions between the orbital functions associated with multi-valley of silicon (Si) quantum dots. Numerical calculations show that the inter-valley coupling between orbital functions increases rapidly with an applied electric field. We also considered the potential applications to the quantum bit operation utilizing controlled inter-valley interactions. Quantum bits are the multi-valley symmetric and anti-symmetric orbitals. Evolution of these orbitals would be controlled by an external electric field which turns on and off the inter-valley interactions. Estimates of the decoherence time are made for the longitudinal acoustic phonon process. Elementary single and two qubit gates are also proposed.