Magnetic and conformational switching in single-molecule transistors

Magnetic and conformational switching in single-molecule transistors

"We study theoretically the inelastic transport through single molecules in the presence of magnetic and conformational degrees of freedom. Particular emphasis is on the dynamical processes that are relevant for writing, storing, and reading information in molecular memory devices. Magnetic anisotropy is found to be crucial for slow spin relaxation. In the presence of a local anisotropic spin we find giant spin amplification: If a bias voltage is applied to a molecule prepared in a spin-polarized initial state, the spin accumulated in the leads can be made exponentially large in a characteristic excitation energy of the molecule. Furthermore, we find a new spin blockade mechanism, if the molecule is coupled to one ferromagnetic and one paramagnetic lead.

Inelastic cotunneling processes in monolayers of magnetic molecules manifest themselves as differential-conductance steps, which are accompanied by much larger changes in the magnetization and lead to the occurrence of additional magnetic sidebands below the Coulomb-blockade threshold.

Current-induced conformational switching in single-molecule junctions is considered for molecules which exhibit two (meta)stable conformations in the neutral state, but only a single stable conformation in the ionic state. We derive and analyze appropriate Fokker-Planck equations and present results for the switching dynamics in general and the quantum yield in particular

Per Hedegaard will also give a short talk on Non-equilibrium and first principle electronic structure.