Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 29: Magnetization Dynamics II

MA 29.7: Vortrag

Mittwoch, 2. April 2014, 16:45–17:00, HSZ 401

Ultrafast electrical control of the exchange interaction — •Johan H. Mentink and Martin Eckstein — Max Planck Research Department for Structural Dynamics, University of Hamburg-CFEL, 22607 Hamburg, Germany

Ultrafast magnetism is concerned with the dynamics of magnetic materials on a timescale of their intrinsic magnetic interactions [1]. The strongest of them is the exchange interaction, which determines the ordering of microscopic spins. In many situations the ultrafast dynamics of magnetization can conveniently be described using (quasi) equilibrium models in which only the (effective) temperature and the magnetization depend on time, leaving the exchange interaction essentially unchanged. Nevertheless, since the exchange interaction is determined by the interactions between the electrons, it can potentially be controlled with electric fields. In this contribution we demonstrate theoretically that ultrafast electrical control of the exchange interactions is indeed possible by studying the Hubbard model out of equilibrium in the regime relevant to Mott insulators and charge-transfer insulators. Furthermore, we show that such ultrafast modification of the exchange interaction can experimentally be detected by measuring the spin resonances that are excited by it.

[1] J. Stöhr and H.C. Siegmann, Magnetism: from fundamentals to nanoscale dynamics, (Springer-Verlag, Berlin Heidelberg 2006).