Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 22: Magnetization Dynamics I

MA 22.6: Talk

Wednesday, April 2, 2014, 10:45–11:00, HSZ 401

Ultrafast Spin dynamics in multicenter Nickel complexes — •Debapriya Chaudhuri, Georgios Lefkidis, and Wolfgang Hübner — Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany

We present ultrafast logic elements in molecular systems with active magnetic centers using ab initio theory and show the possibility of coherent spin manipulation [1]. The processes are investigated in Ni_n (n = 2,3,4) clusters where spin localization, spin-flip, spin-transferability and demagnetization are discussed with respect to their geometries.

We investigate laser-induced, spin-dynamics scenarios on Ni₂ at various interatomic distances. High-fidelity spin-switching is possible within 500 fs with the Λ-process. At each bond length the dimer responds to a specially optimized pulse. Strong correlations are observed and new rules-of-thumb are derived. In case the Λ-process fails, switching is achieved through the M-process that includes more intermediate states with higher occupations. Ni₄ [2] is a good cluster of interest due to its flexibility in achieving local spin-flips and spin-transfers between magnetic centers which occur within 350 fs. Inclusion of higher multiplicities such as quintets in the excited states provides an insight to the phenomena such as reversible global spin-switch and irreversible demagnetization scenarios within 350-400 fs.

[1] G. Lefkidis, G. P.Zhang, and W. Hübner, Phys. Rev. Lett. 103, 217401 (2009).

[2] M. H. Ghatee, and Leila Pakdel, Int. J. Quantum Chem. 113, 1549 (2013).