Control of direct exchange and superexchange interactions with DC electric fields

For many years, much experimental effort has been made for the challenging task of searching for an experimental realization of a theoretical model that can host a novel quantum phase of matter. In general, it is even more challenging to obtain such a model compound with an appropriate parameter set to realize the phase of interest. Accordingly, it is important to control and tune a microscopic Hamiltonian of the model compound by an external field. Recently, two of the authors, Takasan and Sato, discussed controls of phases of quantum spin systems by applying a DC electric field to them. We pointed out that the DC electric field controls the spatial anisotropy of the quantum spin system. In this presentation, as a natural and important extension of our previous work, we discuss DC-electric-field controls of superexchange interactions of geometrically frustrated quantum spin systems that will allow for tuning the microscopic Hamiltonian without changing the composition of the compound. In particular, we give our attention to a way to tune interaction parameters without affecting the spatial anisotropy.