Modelling spin-lattice dynamics

• Applicant: Professor Dr. Ulrich Nowak
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541503763

Spintronics is an important field of research laying the foundation for the development of future applications in nanoelectronics. A key aspect of spintronics is the control, transport, and use of angular momentum as information carrier on time scales down to femtoseconds. However, the understanding of the coupled dynamics of the electronic angular momenta - both spin and orbital contributions - and the lattice degrees of freedom is still very incomplete. The theme of ChiPS - the research unit we apply for - is to link spintronics with the physics of phonons carrying angular momentum. These phonons are circularly polarized and can be chiral (handed), specifically, when the angular momentum is aligned with propagation direction. This new research field calls for new modelling approaches and new numerical tools. In this project we aim to investigate coupled spin-lattice dynamics with atomistic resolution. Methods for the high-performance computation of coupled equations of motion will be developed and exploited. The collaboration with the other theory projects of this research unit will allow for a detailed multi-scale picture of the role of chiral phonons for spintronics, ranging from ab-initio methods via atomistic spin lattice dynamics up to the magneto-elastic theory. Material-specific modelling will benefit from the sample characterization in our research unit and will support the planning and understanding of the experimental projects, including the generation and detection of chiral phonons in the ultrafast and terahertz regime as well as the transport phenomena of chiral phonons. Main goals of the project are the development of parameterized atomistic models for the spin and lattice degrees of freedom as well as their coupling terms, the calculation and investigation of magnon-phonon dispersion relations, and the development and use of modelling tools for coupled spin-lattice dynamics. This project contributes to many central goals of ChiPS, in particular to understanding the relevant length and time scales of chiral phonons, to understanding of the mechanisms behind their formation and decay, to understanding of chiral transport phenomena, to understanding of the hybridization of chiral phonons with other eigenmodes, and to developing and validating multi-scale simulation methods for combined spin-lattice dynamics.

• DFG Programme: Research Units
• Subproject of: FOR 5844: Chiral phonons for spintronics_ChiPS