Electron transport through single-molecule magnets

Maarten Wegewijs

RWTH-Aachen

We have calculated the transport through single-molecule magnets which have an intrinsic anisotropy: terms defining a magnetic easy-axis and transverse terms inducing quantum-tunneling of the magetization vector.
In the non-linear transport regime for weak tunnel coupling we find novel current and noise oscillations induced by the quantum-tunneling of the molecular spin. The distortion of the magnetic properties of molecular magnets upon charging, which is known to occur, is essential for this effect.
In the linear transport regime for strong tunnel coupling we find that the spin-tunneling induces a Kondo effect for any half-integer spin S. Both scaling and NRG techniques demonstrate that the Kondo effect is due to an effektive pseudo-spin 1/2. We find that a high-symmetry of the transverse anisotropy terms can suppress the Kondo effect.