Spin-current switch based on vertical asymmetric double quantum dots containing single manganese

We propose a spin-current switch, which is composed of vertical asymmetric double quantum dots (DQD) containing single manganese, and subjected to an electric field along the growth direction. We demonstrate electrical tunability of charge and spin dependent interdot quantum couplings between two dots. Manipulation of individual Mn²⁺ spin and electrical control of spin-splitting depend strongly on the magnetic impurity position. By sweeping electrical field, the spin-splitting is reduced from its maximum value to zero for Mn²⁺ ion located inside one of the quantum dots. For Mn²⁺ ion inside the other quantum dot, however, the spin-splitting builds up from zero to its maximum value. Hence the spin-splitting may act as a fingerprint of spin- and charge-state of hole in single-Mn doped DQDs, and may also be used as the basis to construct a spin-current switch.