Electric Field Control of Magnetic Coupling in a Double Quantum Dot System and Related Parasitic Electric Dipole Effect

We prove that tunable magnetic interaction in a two-qubit spintronic device can arise due to the mutual competition of the Ruderman-Kittel-Kasuya-Yosida and double-exchange interactions. The values of induced electric dipoles (which arise when magnetic coupling is manipulated by the electric field) are calculated. We show that the dissipation of the energy during logic operations due to these parasitic dipoles can destroy quantum coherence in any quantum dot system.