Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 7: Spin-Dynamics/ Spin-Torque II

MA 7.8: Vortrag

Montag, 23. März 2009, 17:00–17:15, HSZ 04

Light-controlled spin switch in linear metallic chains — •Tobias Hartenstein, Georgios Lefkidis, and Wolfgang Hübner — Department of Physics and Research Center OPTIMAS, Kaiserslautern University of Technology, PO Box 3049, 67653 Kaiserslautern, Germany

We present an ab initio theory for ultrafast spin dynamics in highly correlated materials [1], which includes the spin-orbit interaction and the interaction with external magnetic fields. In particular we analyze optically induced spin-switch processes in linear metallic chains with a magnetic center at each end; in particular Fe, Co or Ni atoms separated by Na atoms. The electronic structure of the ground and excited states of these clusters is determined using high-level quantum chemistry methods. We show that the spin density for low-lying triplet states is located at one magnetic center only. Through the influence of a laser pulse, transitions between different many-particle states are induced and local spin-switch processes can take place. For the purpose of ultrafast magnetic switching, we consider Λ-processes with laser pulses optimized by a genetic algorithm [2]. It is shown that local spin switch due to optical electron excitation can occur on a subpicosecond time scale [3].

[1] G. Lefkidis and W. Hübner Phys. Rev. B 76 014418 (2007)

[2] T. Hartenstein, C. Li, G. Lefkidis and W. Hübner J. Phys. D: Appl. Phys. 41 164006 (2008)

[3] T. Hartenstein, G. Lefkidis and W. Hübner J. Phys. D: Appl. Phys. (in press)