Ultrafast control of exchange interactions in multi-orbital systems

Orateur : Marion BARBEAU (Theory of Condensed Matter group, Radboud university, The Netherlands)

The exchange interaction is the strongest interaction between microscopic spins and at the origin of magnetic order. Recently, the control of exchange has attracted a lot of attention leading to opportunities to find faster and more energy efficient ways to control magnetism [1]. Here we study the ultrafast control of exchange interactions in multi-orbital systems by investigating dynamical strain and ultrashort laser pulses. We find that large modification of Dzyaloshinskii-Moriya interactions (DMI) by acoustic pulses is possible when the electronic hybridization is strong [2]. In addition, we demonstrate that the modification of DMI is sufficient to trigger toggle switching of magnetic skyrmions in thin films. Moreover, we study the effect of high-frequency laser pulses on the control of exchange interactions in a two-orbital spin system. We report that both Heisenberg and the additional biquadratic exchange interaction can be controlled as well as the competition between them.

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