Spin shuttling in a silicon double quantum dot*

Motivated by the demand[1] for long and intermediate range interaction in quantum information devices and recent developments[2,3] we theoretically analyze the dynamics of an electron during a detuning sweep in a silicon double quantum dot (DQD) occupied by one electron, and investigate possibilities and limitations of spin transport. Spin-orbit interaction and an inhomogeneous magnetic field which can introduce errors are included in our model. Interactions that couple the position, spin and valley degrees of freedom open a number of avoided crossings in the spectrum allowing for diabatic transitions and interfering paths. The outcome of a spin shuttling protocol is explored by means of numerical simulations and an approximate analytical model based on the solution to the Landau-Zener problem. We find that constructive interference can ensure a high transport fidelity even for a fast protocol. Exploiting destructive interference between different paths the DQD can also act as a spin or valley filter.

[1] J. M. Taylor et al., Nat. Physics 1, 177 (2005)
[2] T. Fujita et al., npj Quan. Inf. 3, 22 (2017)
[3] A. R. Mills et al. Nat. Communs. 10, 1063 (2019)