Chiral phonons for spintronics
The research unit ‘Chiral phonons for spintronics (CHIPS)‘ wants to understand the physical properties of these chiral phonons in connection with magnetism and spintronics, i.e. in connection with the spin of electrons. How can chiral phonons be generated, transported and recorded? In order to get to the bottom of these questions, the group is looking at time and length scales at the atomic level that have not yet been investigated. This should make it possible to gain new fundamental insights into phonons and potentially identify new spintronic applications. The collaborative effort unites research teams at the University of Konstanz, the University of Augsburg, The Freie Universiät Berlin, the Max-Born-Institut Berlin, the RWTH Aachen, and the Walther-Meißner-Institut.
At the Walther-Meißner-Institute, we focus on the investigation of the nature of angular momentum and its transport through lattice excitations, i.e. phonons. The angular momentum in lattice excitations can be described as the rotational motion of the atoms around their rest position, which can be generated by a suitable superposition of linear vibrations or is caused by the symmetry of the lattice. The investigation of angular momentum in phonons requires the ability to excite phonons in a controlled manner with a defined sense of rotation or circular polarization. For this purpose, we will use magnetic excitations with their precession chirality given by the gyromagnetic ratio by coupling a magnetic system to the phononic system. We plan to study the transfer of angular momentum between the magnetic and lattice excitations, to use this to generate phononic angular momentum and its detection, and thus to study angular momentum transport both in bulk and in phononic micro- and nanostructures with tailored phononic properties.