Ferroelectricity and Strong Spin–Orbit Coupling to Enhance Molecular Spin-Electric Coupling

Abstract

The electric control of magnetism has been considered to be promising for molecular spintronics and quantum information. However, the spin-electric coupling strength appears to be insufficient for application in most cases. Two major factors capable of amplifying the relative effect are spin–orbit coupling and ferroelectricity. Herein, we chose four compounds as examples to study the contribution of spin–orbit coupling and ferroelectricity to spin-electric coupling. The relative orientation-dependent Hamiltonian terms were determined via electric-field modulated continuous-wave electron paramagnetic resonance. The origins of the spin-electric coupling effect in the four compounds are discussed and determined according to the characteristics of the experimental spectra. Meanwhile, the results demonstrated that strong spin–orbit coupling is crucial for producing significant spin-electric coupling and that the effect can be amplified by about 2 orders of magnitude by ferroelectricity. This work can guide the rational screen and design of materials with applicable spin-electric coupling strength, which may provoke techniques including low-power spintronics and precise manipulation of the quantum behavior of spins.