Coherent spin-electric control in a molecular nanomagnet at clock transitions*

Magnetic fields are challenging to localise to short length scales because their sources are electrical currents. Conversely, the control of molecular spins using electric fields is particularly valuable for molecular spintronics because strong electric fields can easily be generated and shielded in within a small volume, allowing addressing of individual spin-carrying molecules in a device [1]. Recently, this has been demonstrated in several molecular magnets [2-4]. However, the spin-electric field couplings (SEC) for those molecules are relatively weak, raising the quest of exploring the pathways for enhancing SEC through molecular engineering.

Here we show that one strategy is to identify a molecule with a significant molecular electrical polarisability and a spin spectrum that is highly sensitive to a structural degree of freedom. We study a molecular nanomagnet, [Ho(W₅O₁₈)₂]^9- [5], in which a small structural distortion leads to a series of ESR clock transitions and a molecular electric dipole. This electric dipole allows us to control electrically the clock transition frequency to an unprecedented level. We demonstrate coherent electrical control of the molecular spin states and independently manipulation for the two magnetically indistinguishable inversion-related molecules in the same unit cell of the crystal [6]. These results pave the way for the use of molecular components in quantum or classical spintronic technologies in which local electrical control can surpass the performance of conventional magnetic spin control.

References:

[1] M. Trif, et al., Phys. Rev. Lett., 101, 217201 (2008)

[2] A. Boudalis, et al., Chemistry - A European Journal, 24, 14896 (2018)

[3] J. Liu, et al., Phys. Rev. Lett., 122, 037202 (2019)

[4] M. Fittipaldi, et al., Nat. Materials, 4, 329 (2019)

[5] M. Shiddiq, et al., Nature, 531, 348 (2016)

[6] J. Liu, et al., Nat. Physics, 17, 1205 (2021)