Electronic control and switching of entangled spin state using anisotropy and exchange in the three-particle paradigm

We explore the control and switching of the entangled spin states of multi-spin particle qubit coupled to an electron using a three-particle spin model described by S-i (i = 1, 2, 3), in which S-1 = 1/2 is an electron and S-2,S-3 can have any spin with both exchange coupling and magnetic anisotropy. We derive a general formula for the existence of a switching (DJ) resonance for any spin S-2,S-3. We further contrast the entanglement switching mechanisms for the S-2,S-3 = 1/2 and S-2,S-3 = 1 spin models. We find that while the onsite magnetic anisotropy in the case of S-2,S-3 > 1/2 allows full control of their spin states via interaction with S-1, in order to achieve acceptable control of a Bloch vector within the S-2,S-3 = 1/2 model, additional mechanisms, such as anisotropic exchange coupling, are required.