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arXiv · 2306.02676

Non-equilibrium dynamics of spin-lattice coupling

Hiroki Ueda·Roman Mankowsky·Eugenio Paris·Mathias Sander·Yunpei Deng·Biaolong Liu·Ludmila Leroy·Abhishek Nag·Elizabeth Skoropata·Chennan Wang Victor Ukleev·Gérard Sylvester Perren·Janine Dössegger·Sabina Gurung·Elsa Abreu·Matteo Savoini·Tsuyoshi Kimura·Luc Patthey·Elia Razzoli·Henrik Till Lemke·Steven Lee Johnson·Urs Staub
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Abstract

Interactions between the different degrees of freedom form the basis of many manifestations of intriguing physics in condensed matter. In this respect, quantifying the dynamics of normal modes that themselves arise from these interactions and how they interact with other excitations is of central importance. Of the different types of coupling that are often important, spin-lattice coupling is relevant to several sub-fields of condensed matter physics; examples include spintronics, high-TC superconductivity, and topological materials. While theories of materials where spin-lattice coupling is relevant can sometimes be used to infer the magnitude and character of this interaction, experimental approaches that can directly measure it are rare and incomplete. Here we use time-resolved X-ray diffraction to directly access the spin-lattice coupling by measuring both ultrafast atomic motion and the associated spin dynamics following the excitation of a coherent electromagnon by an intense THz pulse in a multiferroic hexaferrite. Comparing the dynamics of the two different components, one striking outcome is the different phase shifts relative to the driving field. This phase shift provides insight into the excitation process of such a coupled mode. This direct observation of combined lattice and magnetization dynamics paves the way to access the mode-selective spin-lattice coupling strength, which remains a missing fundamental parameter for ultrafast control of magnetism and is relevant to a wide variety of correlated electron physics.

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Hiroki Ueda, Roman Mankowsky, Eugenio Paris, Mathias Sander, Yunpei Deng, Biaolong Liu, Ludmila Leroy, Abhishek Nag, Elizabeth Skoropata, Chennan Wang Victor Ukleev, Gérard Sylvester Perren, Janine Dössegger, Sabina Gurung, Elsa Abreu, Matteo Savoini, Tsuyoshi Kimura, Luc Patthey, Elia Razzoli, Henrik Till Lemke, Steven Lee Johnson, Urs Staub. 2023-06-05. Non-equilibrium dynamics of spin-lattice coupling. https://doi.org/10.1038/s41467-023-43581-9

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