Electron Mediated Mn-Mn Interaction in Quantum Dots

Abstract

We present a theoretical study of magnetic interaction in quantum dots with magnetic Mn 2+ in dot impurities. We show that gate voltage applied to the quantum dot shifts the centers of electron clouds. Exact formulae for the perturbed spin density allow us to derive expression for the change of the strength of the sp−d coupling. Estimations show that sp−d exchange integral is very sensitive to the gate voltage variations. Exact formulae for the change of the eective exchange integrals are derived. As the spin coded qubits are elements of the RAM memory, a part of the energy stored in magnetic coupling will be dissipated when information is written or erased. We estimate this energy and nd it suciently large to destroy quantum coherence during quantum computing. Finally, we discuss the interdot spin coupling and show the eect of gate voltage operations on the spin intra-and interdot RudermanKittelKasuyaYosida coupling.