Mechanism for nuclear and electron spin excitation by radio frequency current
Sprache des Titels:
Recent radio frequency scanning tunneling spectroscopy (rf-STS) experiments have demonstrated nuclear
and electron spin excitations up to ±12 in a single molecular spin quantum dot (qudot). Despite the profound
experimental evidence, the observed independence of the well-established dipole selection rules is not described
by existing theory of magnetic resonance?pointing to a new excitation mechanism. Here we solve the puzzle
of the underlying mechanism by discussing the relevant mechanistic steps. At the heart of the mechanism,
periodic transient charging and electric polarization due to the rf-modulated tunneling process cause a periodic
asymmetric deformation of the adsorbed qudot, enabling efficient spin transitions via spin-phonon-like coupling.
The mechanism has general relevance for a broad variety of different spin qudots exhibiting internal mechanical
degrees of freedom (organic molecules, doped semiconductor qudots, nanocrystals, etc.).