FOR 5844:  Chiral phonons for spintronics_ChiPS

• Subject Area: Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541503763

Phonons are the fundamental lattice excitations in crystalline materials and usually categorized into acoustic and optical branches. Only recently, it was realized that phonons can also be chiral, carrying angular momentum. Such phonons exist naturally in materials with broken inversion symmetry [21-23, 65] but can also be generated in symmetric magnetic materials by ultrafast demagnetization or via spin-phonon coupling [*1, 66]. These novel developments trigger a set of fundamental questions related to the generation, dynamics, transport and detection of phonons with angular momentum or chiral character, which we will address in this proposed RU. In particular, we aim to 1) understand the basic length and time scales of chiral phonons, 2) understand the mechanisms behind the creation, detection and decay of phonons with angular momentum, 3) understand chiral transport phenomena, 4) understand chiral phonons and their hybridization with other solid excitations, 5) understand and exploit magnon-phonon interaction in nanostructures with the aim to develop tailored phononic environments supporting chiral phonons, 6) assess the potential of phonon-based spintronics as a novel tool for information science.

• DFG Programme: Research Units

Projects

• Advanced magnetic materials for chiral phonons (Applicant Albrecht, Manfred )
• Angular momentum transduction between magnons and phonons in patterned microstructures (Applicant Viola Kusminskiy, Silvia )
• Chiral phonon pumping (Applicant Gönnenwein, Sebastian )
• Coordination Funds (Applicant Nowak, Ulrich )
• Modelling spin-lattice dynamics (Applicant Nowak, Ulrich )
• P4: Ab-initio description of chiral-phonon and spin coupling (Applicant Sharma, Ph.D., Sangeeta )
• Tailoring Phonon Angular Momentum Transport (Applicant Hübl, Hans )
• Ultrafast generation, propagation and detection of chiral phonons (Applicant Kampfrath, Tobias )
• Visualization of chiral phonons in space and time (Applicant Baum, Peter )

• Spokesperson: Professor Dr. Ulrich Nowak