Dr Dmytro Afanasiev will deliver a lecture titled 'Light-driven ultrafast antiferromagnetism'.

An abstract and biography can be found below.

Abstract:

For centuries, the central goal of condensed matter physics has been to understand and describe naturally occurring phenomena, both in macroscopic and microscopic terms. Over the past few decades, a new paradigm has emerged: to experimentally realize and control new states of matter that are not found in nature. In addition to answering fundamental scientific questions, the control and knowledge of potential 'exotic' phases also hold the promise of creating a new and radically different generation of functional devices.

Ultrashort pulses of light are particularly appealing in this context as they allow us to create strongly nonequilibrium transient states of matter with properties that are often not even attainable in equilibrium. Some examples include light-induced superconductivity, metal-to-insulator transitions, and light-driven Floquet engineering. In this discussion, I will explore how light can be used to control magnetism in highly interesting class of the antiferromagnets, encompassing fundamental magnetic interactions, magnetic phase transitions, and highly nonlocal spin dynamics. I will particularly focus on nonthermal methods for controlling magnetism when the photon energy of light is precisely tuned in resonance with elementary excitations, such as lattice vibrations[1], orbitals[2], or electron excitations[3], which have a direct impact on the ordered spins.

References

[1]         D. Afanasiev, J.R. Hortensius, B.A. Ivanov, A. Sasani, E. Bousquet, Y.M. Blanter, R.V. Mikhaylovskiy, A.V. Kimel, A.D. Caviglia “Ultrafast control of magnetic interactions via light-driven phonons” Nature Materials 20, 607–611 (2021)

[2]         D. Afanasiev, J. R. Hortensius, M. Matthiesen, S. Mañas-Valero, M. Šiškins, M. Lee, E. Lesne, H. van der Zant, P. G Steeneken, B. A. Ivanov, E. Coronado, A. D. Caviglia “Controlling the anisotropy of a van der Waals antiferromagnet with light” Science Advances 7, 23 (2021)

[3]         J.R. Hortensius, D. Afanasiev, M. Matthiesen, R. Leenders, R. Citro, A.V. Kimel, R.V. Mikhaylovskiy, B.A. Ivanov, A.D Caviglia “Coherent spin-wave transport in an antiferromagnet” Nature Physics 17, 1001 (2021)

Biography:

Since 2021, I have been an assistant professor at Radboud University Nijmegen in the Netherlands. I received an ERC Starting Grant to establish my own research group, aiming to develop novel methods for controlling antiferromagnets on ultrafast timescales and to interconvert femtosecond pulses into ultrashort spin-wave pulses.