Exploring Spin‐Electric Coupling in an Electrically‐Controlled Rare‐Earth Molecular Qubit

Magnetoelectric materials have attracted considerable interests due to their unique capability to facilitate reciprocal control between the charges and spins in matter. Based on electron paramagnetic resonance (EPR) involving modulated and pulsed electric fields, we have studied a Ce (III)-based molecular qubit under electric control. We observed linear spin-electric coupling (SEC) in the powder sample, which challenges the previous routine of spectral analysis and strength estimation for SEC. We determined the SEC parameter |T_xyz| to be 2.04(16) × 10^-10 m · V^-1, two orders of magnitude larger than the effective value directly extracted from comparing the signal intensity, as validated by our electric-field-modulated (EFM) continuous-wave EPR experiments and simulation program. The coherence time of this Ce(III) qubit is 24.1(13) µs at 5 K with dynamical decoupling and the electric control efficiency is approaching 0.1 Hz · m · V^-1. Our work provides an insight into the EFM detection of the SEC effect of the uniaxial molecule and offers a reference for the coherent electric manipulation of rare-earth molecular quantum systems.