Electric field control of superexchange in multiple linear two-electron quantum dot arrays and mixed-valence molecules

This paper belongs to the area of electrical manipulation of spins in quantum dots and molecular spins for quantum technologies. We propose a theoretical analysis of the electric field controllable superexchange in the two-electron linear arrays of quantum dots ("physical" molecules) and linear mixed-valence molecules based on metal ions in different oxidation degrees ("chemical" molecules) of increasing length. In this view, we consider the kinetic magnetic exchange in trimeric and tetrameric linear arrays of quantum dots and the field dependence of the exchange interaction between electrons. An attainable electric field in these systems is able to essentially change the electronic distribution in the systems under consideration and subsequently to affect the exchange interaction. The numerical estimations demonstrate the feasibility of the revealed effects of the electric field. At a weak electric field, this control is shown to be more efficient for larger numbers of diamagnetic quantum dots mediating superexchange. The peculiarities of chemical analogs of such quantum dot arrays represented by the linear triferrocenium and tetraferrocenium complexes containing two mobile holes are discussed as well.