Giant Spin-Electric Coupling in Heterometallic Porphyrin Dimers

Magnetic molecules exhibiting pronounced spin-electric coupling have long been sought to elucidate the intricate relationship between spin orders and electric fields, as well as to advance the development of multifunctional, energy-efficient devices. Through first-principles simulations and spin superexchange theory, we predict the emergence of giant spin-electric coupling in heterometallic porphyrin dimers. The spin-electric coupling coefficients can reach 1 to 4 orders of magnitude greater than those of conventional two-dimensional magnetic systems. These pronounced spin-electric coupling effects are attributed to the asymmetric spin superexchange pathways between two distinct transition metal centers and their asymmetric response to an applied electric field. This remarkable enhancement enables the modulation of local magnetic moments with practically reachable electric fields, facilitating transitions between ferromagnetic and antiferromagnetic couplings. The discovery of such giant spin-electric coupling and its underlying mechanisms paves the way for the realization of magnetoelectric applications at the single-molecule level.