Coherent ultrafast local spin-switching Λ processes in chainlike nanostructures with two identical magnetic centers

Abstract The laser-induced ultrafast spin-switching mechanism via Λ processes in chainlike nanostructures with two identical magnetic centers (here Co atoms) is systematically investigated using a fully ab initio method. In our recent paper [Physical Review B 84 (2011) 054415], a series of rules of thumb was obtained for spin-switching and spin-transferring Λ processes in charged linear molecular ions with two different magnetic centers. In the present work, the theory is further developed and focuses on neutral systems with two identical magnetic centers. It is found that the chromophore CO molecule plays a critical role in the spin localization in the system by lowering its symmetry. Using Mg as a bridging atom we achieve the so far fastest spin-switching scenario (within 100 fs, an increase in speed by a factor of 3). This demonstrates the necessity for careful engineering of spin-logic units in future nanoscale spintronic devices.