  Electrical control of spins at the nanoscale offers significant architectural
advantages in spintronics, because electric fields can be confined over shorter
length scales than magnetic fields. Thus, recent demonstrations of
electric-field (E-field) sensitivities in molecular spin materials are
tantalising, raising the viability of the quantum analogues of macroscopic
magneto-electric devices.However, the E-field sensitivities reported so far are
rather weak, prompting the question of how to design molecules with stronger
spin-electric couplings. Here we show that one path is to identify an energy
scale in the spin spectrum that is associated with a structural degree of
freedom with a significant electrical polarisability. We study an example of a
molecular nanomagnet in which a small structural distortion establishes clock
transitions (i.e. transitions whose energy is to first order independent of
magnetic field) in the spin spectrum; the fact that this distortion is
associated with an electric dipole allows us to control the clock transition
energy to an unprecedented degree. We demonstrate coherent electrical control
of the quantum spin state and exploit it to manipulate independently the two
magnetically-identical but inversion-related molecules in the unit cell of the
crystal. Our findings pave the way for the use of molecular spins in quantum
technologies and spintronics.
