Strain assisted ultrafast spin switching on Co2@C60 endohedral fullerenes

Strain Effect on the Ultrafast Spin Switching of Cobalt-Doped Carbon Fullerenes

“…Therefore, for the configuration of Co 2 @C 60 studied in the present work, spin switching could be even faster with increasing tensile strain, contrary to our previous investigation on the other two configurations studied in Ref. [29]. On the other hand, when a tensile strain is applied along the direction of the Co-Co bond, although the geometric configuration and spin-density distribution do not significantly change, the obtained spin-switching processes involve many more intermediate states, showing a more complicated procedure, as shown in Figs.…”

“…It is interesting that when a tensile strain is applied along the direction of the Co-Co bond, although the geometric configuration and spin-density distribution does not significantly change, the obtained spin-switching process obviously varies with the increasing strain. Compared with our recent work [29], this phenomenon further confirms that the spin-dynamics properties in endohedral fullerenes can be modulated with strain, showing practical importance, and the concrete spin-switching processes depend on the synergetic effect of both the configuration (symmetry) of the fullerene system and the applied strain.…”

“…Comparing the spin-switching scenarios achieved on the two studied endohedral fullerenes we see that the local spin switching on the Co atom of [Co@C 60 ] + takes less time (around 400 fs) than the simultaneous spin switching on both Co atoms of Co 2 @C 60 (around 800 fs). This is understandable since a nonlocal switching is generally slower than a local one [29]. On the other hand, the local spin switching on [Co@C 60 ] + proceeds smoothly and efficiently during the whole process, while in Co 2 @C 60 , more oscillations are observed (see Fig.…”

“…In numerous ultrafast, laser-induced, magnetization-dynamics scenarios we have already demonstrated that Λ processes can act as exact microscopic spin-transition mechanisms on various bare and ligand-stabilized molecular systems [25]- [27]. In our previous studies we demonstrated that this theoretical model is also effective for the endohedral fullerenes [28], [29]. In our calculations, the two endohedral fullerenes [Co@C 60 ] + and Co 2 @C 60 are geometrically relaxed at the restricted open-shell Hartree-Fock (ROHF) level, in order to obtain the equilibrium structures, as shown in Fig.…”

“…Here, we concentrate on the structure in which the Co-Co bond aligns with the centers of two six-membered rings (HH-type structure in Ref. [29]), because this is a stable configuration whose spin-dynamics behavior has not been studied before. The top and front view of the two relaxed configurations are shown in Figure 1.…”