Coherent electron charge and spin transport in a Silicon double quantum dot*

We investigate coherent electron transport in a Si double quantum dot. First, we focus on the charge dynamics without considering the spin degree of freedom. We propose a scheme to measure the valley phase difference between two dots by using the Landau-Zener-Stückelburg interference, and examine the experimental feasibility of the proposed scheme. We then consider spin transport and clarify how spin-valley mixing can cause considerable flip error even though spin-orbit coupling is relatively weak in Si. Our results also show that the valley phase difference can significantly affect the fidelity of spin transport.